A 75-year-old man was assaulted Friday morning in San Francisco and left with life-threatening injuries, and police say they have arrested a 34-year-old Oakland man in the attack.

The SFPD revealed details of the attack on Monday, as KPIX reports, and it's unclear what the victim's current condition is. The elderly man was allegedly assaulted around 9:15 a.m. Friday on the 400 block of Eddy Street in the Tenderloin. The attacker is said to have severely beaten the victim over the head with a metal bar, and then fled eastbound on foot.

As the Chronicle reports today, police have made an arrest in the case. The suspect has been identified as Peter Nobles, and he was already arrested on Friday after being named by witnesses. Nobles is being held on suspicion of attempted murder,  aggravated assault, elder abuse, and other charges.

The charges also suggest that the victim suffered a brain injury.

Surveillance video and witness descriptions suggest that Nobles struck the victim from behind, knocking him to the ground, and then continued to strike him several more times with the metal bar or pipe.

Nobles was reportedly detained several hours after the attack near the intersection of McAllister and Hyde streets, and police say they recovered what they believe is the metal pipe used in the beating.

We'll update you as we learn more.