WASHINGTON — A Maryland man has pleaded guilty to killing his ex-girlfriend in a parking lot at a Germantown shopping center in June.

Twenty-eight-year-old Donald Wayne Bricker, Jr. entered his guilty plea in a Montgomery County courtroom Wednesday afternoon. He faces a possible sentence of life without parole for the murder of 24-year-old Mariam Sade Adebayo, of Germantown.

Investigators say the killing happened after Adebayo broke off their relationship and Bricker texted her repeatedly, demanding to see her to find out if she was already dating someone. Adebayo agreed to meet him — in a public place — the parking lot of a Target department store. The two got into Adebayo’s car, where they argued. Police say she bolted, he followed and fired at her.

When Adebayo fell, he walked up to her, and according to court documents, aimed the weapon at her face, and fired again — killing her.

Bricker, a registered sex offender,  was barred from owning firearms because of his felony record, but managed to buy a black powder revolver — a replica — through the mail. The revolver is unregulated under Maryland law, and so the purchase was legal, according to prosecutors.

Bricker will be sentenced on Feb. 26.