Michael Wayne McGray is led into court in Moncton Tuesday, March 3, 1998. McGray claimed responsibility for 16 slayings Thursday, March 23, 2000, some as far away as Seattle, and said the urge to kill remains in him like a hunger. (Supplied)

The “Homicidal Drifter,” a serial killer already serving six concurrent life sentences, pleaded guilty Monday to a jailhouse murder in B.C. last year.

Michael Wayne McGray, 47, pleaded guilty to the first-degree murder of Jeremy Phillips, 33, while serving time at Mountain Institution in Agassiz, B.C., last November.

The killer had previously declared he would murder a prison guard, an inmate or anyone else who would quench his seemingly insatiable hunger to take lives.

McGray claims to have killed 16 people across North America since his deadly rampage began in 1985.

“The only thing that I regret is that it ended,” he told a reporter last year from a prison cell in New Brunswick.

It’s not the first time the Nova Scotia native had pleaded guilty to his crimes. He previously admitted to the stabbing deaths of teenager Elizabeth Gale Tucker and Saint John, N.B., resident Mark Gibbons, among others.

McGray also admitted to targeting vulnerable gay men and prostitutes after being left on his own as a teen.

As a child, the killer suffered from sexual abuse and had been beaten by his father from a young age.

He was sentenced to life with no chance of parole for 25 years.