Police say the incident started as a domestic argument. The suspect went to his ex-wife's home Thursday morning and got into a violent dispute.
Detectives confirmed there was a restraining order on file for the man.
"The mother-in-law, we believe, tried to intervene and was also attacked and succumbed to her injuries at the scene," LAPD Lt. Ted Matthews said.
Police say the suspect left and went to the Colorado Blvd bridge in Pasadena near the Rose Bowl. There, he jumped to his death.
There were reports that the suspect may have been heading to his son's school. The 6-year-old boy was taken by police and is now safe with relatives.
Neighbors said they never heard any arguments between the couple, but were aware of the restraining order.
Police are still investigating the killer's motive.