OKLAHOMA CITY - We're learning more details about a violent stabbing on I-35.
That's where a pregnant woman got attacked on the busy highway over the weekend.
Moments later, the suspect jumped into the Oklahoma River.
Out of nowhere the suspect attacked her with a knife.
"I knew something bad was going to happen, but I wasn't expecting that," said Michael Peck.
Michael knows both the victim and suspect.
The couple lives together in an apartment building on NW 5th.
Neighbors say fights between the pair were common.
"I mean he was bound to snap sooner or later," said Peck.
The suspect, Christian Hillard appears a little banged up, but did survive his plummet into the river.
Police also arrested Hillard just two weeks ago for setting fire to the couple's apartment.
"He was a time bomb. I don't know how she didn't see that coming," said Peck.
Despite that history, exactly why Hillard allegedly attacked his girlfriend, who's currently 8 months pregnant, remains a mystery.
"It doesn't appear there was any reason. She said as they were driving along. He said he felt strange and then began stabbing her. Nothing provoked this," said Oklahoma City police Sgt. Jennifer Wardlow.
The suspect was booked into jail on a charge of assault with dangerous weapon.
He's also being held on a separate charge of arson.
The victim is expected to be okay.