A man already locked up for murdering homeless men in both Montana and Charlestown was arraigned for the murder of two others in Lowell and Cambridge.

Kevin Lino, 38, formerly of Lowell, was arraigned in Middlesex Superior Court on two counts of first-degree murder for the 2010 death in Lowell of Gary Melanson, 54, and the 2012 death in Cambridge of Douglas Leon Clarke, 30.

Clerk Magistrate Daniel Flaherty ordered Lino to be held without bail. Lino, who stands out with significant tattoos including a star under his right eye and a spiderweb across his forehead, is next due in court on Oct. 3.

"These allegations demonstrate a violent pattern of behavior in which the defendant is alleged to have targeted and victimized some of the most vulnerable members of our communities," Middlesex DA Marian Ryan said. "These cases, not initially ruled by the Medical Examiner to be homicides, left the families and friends of Mr. Melanson and Mr. Clarke with little or incorrect information about what had happened to them."

Lino was only 23 years old when prosecutors say that he beat the "much smaller and older" Melanson to death with a metal bat after the older man continued to light fires for warmth in their encampment after Lino told him not to.

"The defendant believed that the fires attracted attention from police and fire department personnel, and he did not want to draw such attention to the area," according to a Middlesex District Attorney statement.

After getting tipped off by an anonymous caller, Lowell Police found Melanson's mangled body atop a collapsed tent under the Rogers Street Bridge on Nov. 29, 2010. An autopsy concluded that he had blunt impact injuries all over, including his head, and suffered fractures to his rib and left arm as well as a collapsed lung. At the time, the medical examiner listed his manner of death as "undetermined."

Then on Aug. 2, 2012, Cambridge Police checked on a report of an unconscious man in the 900 block of Memorial Drive along the banks of the Charles River.

There they found the body of Clarke, a homeless man who often went by the name "Rage." He was found to have morphine, codeine, alcohol and gabapentin -- an anti-seizure drug sometimes abused recreationally -- in his system and his death was deemed an "accident," simply "a result of acute and chronic substance abuse."

But in 2018, the Middlesex DA Cold Case Unit discovered evidence that these deaths were no accident, they say, and identified Lino as a suspect for the murder of the two men.

While investigating Lino for an unrelated matter, prosecutors say the unit uncovered details of Lino's relations with the two men. While Melanson had obviously been beaten, Lino's death was less obvious..

Prosecutors say that both Lino and Clarke lived as a part of a homeless group that gathered around the Harvard MBTA station and that Lino "allegedly decided to take it upon himself to drive out heroin-using members of the group, including by assaulting many of them throughout the day."

"After a confrontation with the victim, Kevin Lino allegedly resolved to punish the victim for his insolence by poisoning him and offered the victim a quantity of heroin that he knew would cause an overdose," according to a DA statement.

Middlesex DA Marian Ryan said during a press conference last week that the allegations against Lino -- and two earlier murder convictions -- "demonstrate a very violent pattern of behavior, alleging a targeting of some of the most vulnerable members of the community."

Lino had previously pleaded guilty to the homicide of a homeless man in Montana in 2013 and in 2019 to the 2012 fatal beating of 45-year-old Normand Varieur in Charlestown.

Since 2019, Lino has been serving a life sentence for the Charlestown slaying and a concurrent 40-year-sentence for the conviction from Montana.