San Francisco police are investigating an attack after a tech co-founder said he was struck in the head with a metal pipe in the Mission District. 

A witness told police the victim, 33, and another man got into an argument that escalated into a fight in the area of 24th and Bryant streets around 2:10 a.m. Jan. 18. The San Francisco Police Department did not provide other details about the attack or the extent of the victim’s injuries, except to say he was bleeding from the head. 

Paramedics took him to a hospital for treatment, police said. 

The assailant took off after the attack and had not been arrested as of Sunday. 

The investigation is ongoing, with investigators “working to make an arrest in this case,” the department said Sunday on X. 

“Violent crime is unacceptable in San Francisco and the SFPD has devoted resources to ensure the public is safe and perpetrators are held accountable,” the department said.

In a series of posts on X, the apparent victim — Vishnu Hari, co-founder of Ego, a San Francisco-based AI-powered 3D simulation engine, according to his X and LinkedIn accounts — said he was discharged from a hospital’s intensive care unit recently. 

Calling the attack unprovoked, he said he was struck in the back of the head with a metal pipe as he walked home from a corner store. The account was based on information he gathered from friends; he has no recollection of the incident, he said. 

Hari said he suffered a traumatic brain injury, and that the attack left him partially blind in his right eye and unable to hear well out of his left ear. He expects it will take several months to heal, he said. 

The assailant did not steal his phone or wallet, but did rip off his jewelry, Hari said on social media. 

Hari did not respond to a request for comment Sunday.