A man pleaded no contest today to killing a man who had arranged to sell a gold necklace to him in Montebello three years ago, the Los Angeles County District Attorney's Office announced.

Sean Matthew Garcia (dob 4/7/90) entered the plea to one felony count each of first-degree murder and second-degree robbery and admitted using a gun in the commission of the crimes.

Deputy District Attorney Lindley Heher said Garcia was immediately sentenced to 41 years to life in state prison.

Prosecutors said victim Brian Gomez, 28, arranged to sell a gold necklace to Garcia through a sales app. On Sept. 28, 2015, the two men met in the 1600 block of Neil Armstrong Street. Garcia, who carried an assault rifle, chased Gomez and fired twice at his feet when the victim stopped.

Gomez then charged at the defendant and Garcia shot the victim in the head and killed him, the prosecutor said.

Garcia also pleaded no contest to stealing an assault rifle from its owner in August 2015.

Case BA440271 was investigated by the Montebello Police Department.