The man who prompted an Amber Alert after taking off with his four young kids allegedly stabbed his girlfriend's friend to death as she desperately tried to call 911 during a terrifying knife attack, according to an eyewitness to the slaying.

Greenland Etienne was killed sometime before 1 a.m. today inside her Lynn apartment, according to a friend and a relative, and now police say they want to question Rodlyn Petitbois, 25, in connection with the murder.

Etienne heroically tried to stop the violence, the eyewitness said.

An Amber Alert was issued today for Petitbois, his girlfriend, Louna Eveillard, 26, and their four kids, aged 11 months old to 3 years old, who were last seen leaving Etienne's home at 1 a.m.

Sabinio Stpruex, 23, of Lynn said Petitbois stabbed Etienne as she tried to call 911 after a drunken Petitbois stabbed Eveillard in the hand, locked the home's doors and threatened to stab Stpruex.

"She was trying to help Louna," said a shocked Stpruex, who witnessed the knife attack and is one of Etienne's close friends. "He stabbed Greenland when she said she's going to call."

Stpruex said Etienne was home at 99 Rock Hill Road at 11 last night when Eveillard showed up with her four children seeking refuge from Petitbois.

Soon after, Petitbois, 25, showed up and started terrorizing them and tried to force Eveillard to leave with him, Stpruex said.

"(Eveillard) said, 'I'm not going nowhere," Stpruex recalled. "He said, 'Let's go.' He went to the kitchen and grabbed a knife and he tried to stab Louna in the hand. Louna put out her hand in his face."

He said Petitbois also came at him with a knife and at one point Eveillard begged him to spare everyone else.

"Louna said, 'Kill me,' " Stpruex said. "Don't hurt anybody in the house, just kill me."

That's when Etienne stepped in, he said.

"Greenland said, 'Enough, I'm going to call the cops," and walked into the hallway, Stpruex recalled. "He went into the hallway and stabbed Greenland in the eye and when I seen that, I heard a voice say, 'Oh my God.' "

He said Petitbois then ran out and Eveillard followed with the children. He said the children were in another room when Etienne was stabbed.

State Police say Eveillard was not a willing participant in the kidnapping.

Asline Etienne, 35, who also identified the victim as Greenland Etienne, said her sister had four children, aged 5 to 9, but they were not home during the knife attack.