DALLAS (CBSDFW.COM) – A teenager accused of sexually assaulting an 88-year-old woman in her Lake Highlands home on October 8 was enrolled in a high risk community supervision program last month, at the same time another case of aggravated robbery was dismissed against him.

When a Dallas police officer spotted suspect Kristopher Brown on the afternoon of October 9 at a gas station on Skillman Street, officials say he was filling up the gas tank of his latest victim and that the antique shotgun he’d taken from the woman was visible through the back window of her stolen Lexus.

Brown, 19, now has federal charges against him for carjacking and possession of a stolen firearm.

An arrest affidavit shows the victim awoke early Tuesday morning to find a man in her bedroom. Police say the man punched her in the face, giving her a black eye, then tied her to a chair and disabled her phones.

In a statement, U.S. Attorney Erin Nealy Cox said Brown also “brutally sexually assaulted” the woman.

According to the affidavit, the robber stole money from the victim, her shotgun, and her Lexus. Police say, before leaving the suspect told the victim that in five days she could find her car at an apartment complex on east Overton, even writing the address down on an envelope.

The location of the complex is directly across the street from where court records show Brown living earlier this year. Those records also reveal Brown was still under community supervision for an aggravated robbery he committed in 2016 — when he was 16 years old.

The teen was charged with aggravated robbery again late last year and was wearing an electronic leg monitor awaiting trial, but prosecutors with the Dallas County District Attorney’s Office last month requested the case be dismissed saying they wouldn’t be able to meet the burden of proof.

Court records show he was ordered to enroll in a class aimed at rehabilitating offenders and participate in Dallas County’s High Risk Caseload Diversion program.

Cox said the U.S. Attorney’s Office chose to pursue the latest case against Brown because of the egregious nature of the crime, knowing federal charges often result in harsher penalties. According to a spokesman, the officer is able to take the case on the grounds the crime affected interstate commerce, and because it involved a gun and a car neither of which were manufactured in Texas.