BRIGHTON, Colo. (AP) — A Colorado man pleaded guilty to three counts of first-degree murder Wednesday as part of a plea agreement that calls for him to serve life in prison without the possibility of parole after opening fire inside a crowded Walmart in suburban Denver.

Scott Ostrem, 48, also pleaded guilty to one count of attempted first-degree murder for endangering 45 other people inside the store in Thornton on Nov. 1, 2017.

Adams County District Attorney Dave Young said Ostrem, through his attorneys, approached prosecutors in August offering to plead guilty in exchange for a life sentence.

At the time, Young said he was still considering whether to seek the death penalty against Ostrem. During discussions about the death penalty, Young said victims’ relatives “were unanimous” in wanting a quicker resolution to the court proceedings.

Police have said Ostrem walked into the store on a weekday evening, fired seven shots in about 20 seconds and left without saying a word.