REVEALED: Soldier who killed Vanessa Guillen was 'tipped' off by news reports on her remains being found and escaped his guard before taking his own life - as chief investigator says he DIDN'T sexually assault her

The Fort Hood soldier accused of killing Vanessa Guillen escaped a guard when he read news reports that her remains were found, got a gun, and killed himself in a police chase, it has been revealed.  

The embattled Killeen, Texas Army base fell into the national spotlight in April with the disappearance of 20-year-old Guillen, who told her family she was being sexually assaulted at the base by a superior.

She was allegedly killed in an arms room by fellow soldier Spc. Aaron Robinson on April 22, who was ranked above her at the time.

He allegedly killed Guillen with a hammer, picked up his girlfriend Cecily Aguilar and they dismembered and buried her remains near the Leon River in Belton.

Officials say excessive news coverage of the discovery of Guillen’s remains 'tipped' Robinson off to flee as read the updates on his phone.

Vanessa Guillen's accused killer Spc. Aaron Robinson, 20, escaped a guard when he read news reports that her remains were found, got a gun, and killed himself in a police chase, Army officials reveal

The drawn out investigation into Guillen took so long because Robinson, at first, had an alibi.

Though he was the last person to see her alive, three soldiers saw Guillen when they smoked outside the arms room by a nearby tree the day she vanished.

The testimony of those three soldiers threw off the investigation for an entire month, Maj. Gen. Donna Martin, the Army’s provost marshal, who leads the Army’s Criminal Investigation Command, said to ABC's 20/20 in a new special that will air Friday.

They said they saw her leave at 'a time that would’ve indicated she had left Spc. Robinson’s arms room.'

There were no cameras near the parking lot of the arms room and the investigation centered around the parking lot.

'They filled out affidavits that said they had seen Vanessa at a different time from when she had actually departed the other arms room,' Army Secretary Ryan McCarthy said to the show.

'So that gave … essentially an instant alibi for Spc. Robinson, even though they had not really known the correct time of when she had actually departed and headed to the parking lot,' McCarthy said.. 

'The trail went cold for about a month,' he added.

Robinson spoke with investigators several times and they found he had called his girlfriend Aguilar multiple times the night Guillen disappeared.

This raised suspicion because he initially told investigators he had been with Aguilar all night.

Aguilar also changed her story, claiming she and Robinson went on a drive to look at the stars that night, according to court documents.

On June 30 investigators found remains near the Leon River that were later identified as Guillen.

That same day Robinson was placed in a room under the watch of an unarmed escort, as investigators grew suspicious of his involvement in Guillen’s death.

His phone pinged late at night in the same area where Guillen’s remains and his alibi unraveled.

'The media broadcast was really kind of what we believe to be the tipping point for Spc. Robinson to flee,' Maj. Gen. Donna Martin, the Army’s provost marshal, who leads the Army’s Criminal Investigation Command, said. She added an investigation found Robinson did not sexually harass Guillen

Army Secretary McCarthy says he doesn't know if there will ever be justice for Guillen, but 'it's clear' the Army let Guillen's family down. 'We have to find answers and we will hold people accountable,' he said to 20/20

He wasn’t officially detained but was under the watch of a guard, Army officials say, and was able to get away.

'He was not in police custody because of the legal process works,' Martin explained.

He managed to escape and his escort chased him as he ran from the base.

'He gets in a vehicle and he flees and he leaves Fort Hood,' Martin said, though it’s not clear how he was able to access a car.

Local law enforcement chased Robinson and stopped his car. 

As they closed in he shot himself.

Army officials are not revealing when or where he got the gun but Martin said the 'firearm, I can tell you, was not a government weapon. So he did not get it from his arms room.'

Martin blamed his escape on news coverage of Guillen’s remains for 'tipping' him off, as he read about the investigation's developments on his phone.

'All of this is unfolding at the same exact time… What we didn't maybe expect was the media broadcast,' Martin said.

'The media broadcast was really kind of what we believe to be the tipping point for Spc. Robinson to flee,' she added.

Vanessa Guillen, a Houston, Texas native, disappeared from Fort Hood on April 22. Her remains were found on June 30

The base in Killeen, Texas has reported 28 soldier deaths this year alone 

Guillen reported that she was sexually harassed at the base by a superior, but didn’t say who was behind it.

Robinson, a 20-year-old soldier from Calumet City, Illinois who was deployed to Iraq for seven months in 2018, was a specialist ranked above Guillen, a private first class, at the time.

'My daughter didn’t give me a name. But I begged Vanessa’s friend so much…and she said, "Yes, yes, there is a man: Robinson,"' Gloria Guillen, Guillen’s mother, said to 20/20.

'I was told that he followed her into a shower. And there was another person that also harassed her, used vulgar words,' Natalie Khawam, the Guillens’ family attorney said.

However, Martin says that there’s no proof Robinson harassed Guillen.

'In our criminal investigation, we found no evidence of sexual harassment between Vanessa and Spc. Robinson…That was ruled out very early,' she said.

'My daughter didn’t give me a name. But I begged Vanessa’s friend so much…and she said, "Yes, yes, there is a man: Robinson,"' Gloria Guillen, Guillen’s mother, said to 20/20. Glorida pictured center at her daughter's memorial service on August 14 in her hometown of Houston, Texas 

She believes the shower incident was a misunderstanding with a completely separate soldier rather than Robinson.

Martin said during field exercises soldiers use baby wipes to clean themselves and referred to it as a 'hygiene shower'.

'She was actually behind a bush and she was conducting field sanitation,' Martin said.

'Her platoon sergeant may have walked by and heard some noise… He called out and said, "Is there someone there?" She identified herself. And he said, "What are you doing?" And she says, "I'm conducting personal hygiene." And that was the encounter,’ Martin explained.

Army Secretary McCarthy says he doesn't know if there will ever be justice for Guillen, but 'it's clear' the Army let Guillen's family down. 

'We have to find answers and we will hold people accountable,' he said to 20/20. 

But Fort Hood's scandals are far from over. 

The base has reported 28 soldier deaths this year alone, at least five of them deemed suspicious. 

On Tuesday it was announced Congress will investigate the sexual assault, disappearances and death going on at the base. 

20/20 airs on Friday, September 11  at 9pm - 11pm EST on ABC

Timeline of Fort Hood disappearances/deaths

February 1, 2020: PVT Eric Christopher Hogan and PFC Anthony Nevelle Peak Jr. die in a car crash 

March 1, 2020: SPC Shelby Tyler Jones is shot dead at a convenience store in Killeen 

March 5, 2020: Spc. Christopher Wayne Sawyer found dead at his home. Foul play is not suspected.  

March 14, 2020: SPC Freddy Beningo Delacruz Jr. is killed in a triple murder

March 23, 2020: Fort Hood soldier Spc. Jovino Jamel Roy, 22, was charged with murder after allegedly shooting former Fort Hood soldier Michael Steven Wardrobe, 22 

April 22, 2020: Vanessa Guillen goes missing and is last seen in the parking lot of the base. She disappeared after telling her family she was being sexually harassed by a sergeant on the base.

May 18, 2020: Body of Army Pfc. Brandon S. Rosecrans, 27, was discovered with gunshot wounds and his Jeep was found three miles away engulfed in flames.

June 19, 2020: Search teams discover the corpse of missing soldier Pvt. Gregory Wedel-Morales following a tip to Army base investigators. Remains were found in a field in Killeen, just over 10 miles from Stillhouse Hollow Lake, five miles from Fort Hood.

July 1, 2020: First parts of Giullen's remains found about 20 miles east of Fort Hood.

Spc. Aaron Robinson, 20, kills himself. Officials say he killed and dismembered Guillén and had the remains disposed of. 

July 17, 2020:  Pvt. Mejhor Morta, 26, of Pensacola, Florida was found dead July 17 in the vicinity of Stillhouse Hollow Lake, around 15 miles from the Fort Hood base.

August 2, 2020:  The body of Spc. Francisco Gilberto Hernandezvargas, 24, is recovered from Stillhouse Hollow Lake following boating incident not far from where Morta was found.

August 12, 2020: Spc. Cole Jakob Aton, 22, of Kentucky died after he was hit by a car as he was assisting a minor accident scene 

August 13, 2020: National Guard soldier, Sgt Bradley Moore dies during a training exercise at the base 

August 19, 2020: Sgt. Elder Fernandes, 23, is reported missing after he was last seen on August 17.

August 25, 2020: The body of Fernandes is believed to have been found about 30 miles from Fort Hood