A man has killed his ex-girlfriend's parents and held her younger brother hostage in an apparent revenge attack after their relationship ended.

Mirza Tatlic, 24, was eventually shot dead in a standoff with police at the San Jose home belonging to the parents of his ex, Rachel Prabhu.

He and Ms Prabhu's relationship ended last year but Tatlic appeared not to have got over the break up, comparing her to the devil in rambling Instagram posts.

Tatlic went to Prabhu's family home on Wednesday night. Prabhu, who lives in another state, was not there.

Rachel Prabhu ended her relationship with Tatlic last year. Photo / Twitter
Rachel Prabhu ended her relationship with Tatlic last year. Photo / Twitter

According to CBS Tatlic shot her father Naren Prabhu, a Silicon Valley tech executive, in the doorway before killing her mother inside. Mr Prabhu reportedly had already taken out a restraining order against Tatlic.

Police were alerted by a call from the couple's 20-year-old son, who escaped the house during the shooting.

After police arrived at the scene Tatlic used Prabhu's 13-year-old brother as a human shield in a two-hour standoff during which he reportedly called Prabhu.

At one point during the standoff Tatlic told police he killed Prabhu's parents to cause her pain in retaliation for the break up, The San Jose Mercury reported.

San Jose police Chief Eddie Garcia told the paper that "the extent of how that really got to this individual remains to be investigated and thoroughly vetted out."

The paper reported that Tatlic eventually released the 13-year-old who could be heard crying and asking the cops, "What am I going to do with my life now?"

Tatlic was shot dead by a police marksman after he appeared at a window inside the house and pointed a handgun at police.

Chief Garcia called it "a tragic incident perpetrated by evil," adding that Tatlic had a history of mental illness, domestic violence and driving under the influence.