Pasadena police said Steven Torrez, a father of three, was murdered by a man who appears to be a complete stranger.
Early Sunday morning, police said Torrez was outside on the patio of his girlfriend's apartment. She said around 2:45, the suspect, identified as Omari Chambers, showed up and started ranting to himself.
"My boyfriend just responded like, 'What are you talking about. What are you doing?,'" said Ashley Lane, Torrez's girlfriend.
His girlfriend said after that, the suspect walked up the stairs and seconds later stabbed Torrez.
"Stabbed him in the leg. Steven did not touch him. Not a finger," said Lane.
Police said Chambers hit an artery. Torrez died soon after, leaving behind his three children -- ages 2, 8 and 11.
Loved ones said Torrez worked his whole life for his children.
"He lost his dad at a very young age so that made him want to be a better dad to his children," said Lane.
Torrez was set to complete pipe fitting school next week. He was working to better his life, to make more money for his kids.
His family has set up a GoFundMe account to pay for funeral expenses and costs for the children.
Chambers is charged with murder.