CNN  — 

Closure may come to two families in Colorado as authorities announced they had charged a man with killing four people more than 30 years ago.

At a joint news conference Friday in Aurora, law enforcement officials said they issued arrest warrants for Alexander Christopher Ewing, 57, whose DNA linked him to the cold cases, authorities said. Ewing is in the custody of the Nevada Department of Corrections on separate charges.

The gruesome killings began on Jan. 10, 1984, when Patricia Smith was found dead in her home in Lakewood, about a 7-mile drive from Denver, authorities said. Six days later, on Jan. 16, Bruce Bennett was found dead with his wife, Debra, and their 7-year-old daughter. The couple’s 3-year-old daughter was severely injured, but survived. Both children, police said, had been sexually assaulted.

While investigators saw similarities between the killings from the start, the release said technology was limited. The investigations remained open, authorities said, but they were considered cold cases for over 30 years.