A 34-year-old Dorchester man was ordered held without bail today in the killing of 13-year-old Tyler Lawrence, as Suffolk District Attorney Kevin Hayden vowed to bring the suspect to justice.

Csean Skerritt is accused of gunning down Lawrence in Mattapan on Jan. 29 as the teen was walking down the street after visiting his grandparents.

In Boston Municipal Court on Friday, Suffolk County Assistant District Attorney Julie Higgins asked the judge to deny bail, describing Skerritt's past criminal history and how video evidence captured a brazen attack that morning.

"Video shows the defendant walking down Fremont [Street]," Higgins said. "The defendant sees Tyler walk by, and the defendant then approaches Tyler. Moments later, the fatal shots are fired and the defendant is then captured on video running from that intersection with an object in his hand consistent to a firearm."

Higgins said Lawrence was shot five times, including in the head.

"Evidence has revealed so far that there is no connection between this defendant and Tyler Lawrence," she told the judge. "In light of the defendant's lengthy criminal history, and the strength of the evidence against this defendant for murdering Tyler Lawrence, the commonwealth is asking that this defendant be held without bail."

Speaking outside the courthouse, Suffolk County District Attorney Kevin Hayden said law enforcement don't know why Skerritt allegedly shot Lawrence.

"What would allow a 34-year-old man with evil intent to decide to shoot a 13-year-old boy five times at 11:30 on a Sunday morning, steps away from churches?" he asked. "I don't know. We may never know."

Hayden went on to say that the motive doesn't really matter, and vowed to hold Skerritt accountable.

"We spend too much time worrying about who did what and why," he said. "What we need to worry about is the heinous act that was committed by this evil man. We're going to hold him accountable for that. We're going to do everything we can to hold him accountable for that."

Hayden emphasized that Lawrence was a young boy "that was taken away from us far too soon."

Skerritt is due back in court next month. Prosecutors said they expect an indictment on murder charges to be returned within 30 days.