A man has been charged with first-degree murder in the shooting death of a 22-year-old woman at a northwest Oklahoma City park more than five years ago.

Alex Po faces a charge of first-degree murder during the commission of a robbery in the death of Cierra Abbott, according to charging documents from the Oklahoma County District Attorney's Office, as reported by KOCO. Abbott was 22 at the time of her death.

What court documents allege

A witness who was with Abbott told responding officers that two suspects approached their car at the park, according to the court documents. One of the suspects pulled out a handgun and took marijuana from them.

The documents state the shooter then asked Abbott what she was going to do. When she pulled a gun from her seat, the suspect fired.

Po was 18 at the time of the crime, News9 reported. The arrest warrant states Po shot and killed Abbott while committing robbery, according to News9.

How investigators linked Po to the crime

Detectives reviewed it in March 2023 and identified an Instagram account they believed belonged to Po, according to the affidavit cited by KOCO.

Investigators then compared that Instagram account with a Snapchat account that had been used to communicate with Abbott. They determined both accounts were connected to the same person based on similarities in usernames and other information, the affidavit states.

Suspect already in custody

Po, now 23, was incarcerated in 2023 in a separate case, according to KOCO. News9 reported he is being held at Allen Gamble Correctional Center for a separate robbery.

He now faces the new first-degree murder charge on top of that sentence.

Neither KOCO's nor News9's reporting mentions whether the second suspect described in the witness account has been identified or charged.