DENVER (CBS4)– For the first time since 1999, prosecutors in Denver are seeking the death penalty.

Denver District Attorney Mitch Morrissey filed the legal paperwork on Thursday to seek the death penalty against Dexter Lewis, one of three suspects in the quintuple murder at Fero’s Bar, last fall.

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On October 17, 2012 the initial call came in as a fire at Fero’s Bar and Grill on Colorado Boulevard. But when investigators went inside, they found a grisly murder scene.

Five people had been stabbed to death. Investigators said the fire was set to cover up the killings.

Morrissey said he’s never seen such a horrific crime in his 30 years with the Denver District Attorney’s Office.

“We have a man and four women who were allegedly laid down on the floor of a bar and butchered.” Morrissey continued, “And based on that, I think it is appropriate to seek the death penalty.”

Police said Lewis, 23, a known gang member who was on parole at the time of the murders, was eating inside the bar before the killings.

Lewis texted his friends Joseph and Lynell Hill to join him. They entered wearing Halloween masks and held everyone inside at gunpoint. But, police say it was Lewis who slaughtered the five victims; Daria Pohl, 22, Kellene Fallon, 45, Yung Suk Fero, 63, Ross Richter, 29 and Teresa Beesley, 45.

Young Fero, Teresa Beesley, Kellene Fallon, Daria Pohl, Ross Richter were killed in Fero's Bar & Grill on Oct. 17. (credit: CBS)

Young Fero, Teresa Beesley, Kellene Fallon, Daria Pohl, Ross Richter were killed in Fero’s Bar & Grill on Oct. 17. (credit: CBS)

“Mr. Lewis killed every one of the individuals that were murdered in this case.” Morrissey explained, “Neither of the Hills was actually involved with wielding the knife with any kind of fatal wounds to these victims.”

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Earlier this week, the Hill brothers both took plea deals for their roles in the murders. Both were spared the death penalty in exchange for their testimony against Lewis.

In court, Lewis wore a red Denver jail jumpsuit and was backed by a handful of family members who questioned whether Lewis was getting adequate representation.

Tracy Jimmerson, Lewis’ uncle, asked the court to replace Lewis’s lawyers – but the judge said that request would have to come from Lewis himself.

Jimmerson said Lewis hung around with the wrong people and must have been in, “the wrong place at the wrong time.”

He said that Lewis took part in anti-gang programs a number of times and was an aspiring musician.

Lewis’ father was reportedly a member of the same gang as his son and was killed in gang violence.

“I believe he’s not guilty,” he said. “He’s my nephew; he told me he wasn’t guilty. He’s a good kid.”

The State of Colorado hasn’t put anyone to death since 1997.

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– Written by Brian Maass and Mark Ackerman for