The man whose body was found in a Castro Street apartment Tuesday night has been identified as Robert Christopher, 56.

[Updated August 1: Late Friday, San Francisco police issued a statement that the medical examiner has determined that the manner of Christopher's death was a homicide.

SFPD also issued an alert seeking the public’s help in locating David Wehrer, a 26-year-old white male, 6 feet 1 inch tall, 155 pounds, with brown hair, and possibly a black eye and a few days of facial hair growth. Wehrer is believed to have been seen with the victim and in the victim's home recently, police said.]

Christopher was apparently gay, according to Lieutenant Mike Stasko, head of the San Francisco Police Department's homicide unit.

"From what I understand, the individual was gay," due to communications "in regards to other persons the victim was living with or having a relationship with," Stasko said today (Thursday, July 30).

Stasko said there was one other resident of the flat, located at 98 Castro Street that police know of, whom they haven't located. He said he did not know if the other resident was Christopher's partner.

Alan Pringle, chief investigator for the San Francisco medical examiner's office, said the cause of death is still under investigation, and will probably not be determined for several weeks. Pringle said that's standard.

Stasko would not say what Christopher's injuries were, and he said a motive hasn't been determined.

"Until we can find the other resident and determined a suspect, we're not going to have any idea why this happened," said Stasko.

Stasko said police were determining what to do with additional search warrants and forensic evidence to help identify a possible suspect.

Pringle would not say how long Christopher had been dead. Stasko said that Christopher had been dead "anywhere from a couple of days to a week."

He also said the apartment was in disarray, but because of the amount of books, furniture, and other items, "not necessarily from a struggle or anything else. Basically, it was the way the flat was kept."

Pringle said Christopher's family does not live in San Francisco, but he could not disclose where they live.

Stasko said there were "a lot of pets" in the flat, including a rabbit, a fish, an iguana, and a couple of dogs. He didn't know the animals' condition but said they've been taken in by the Society for the Prevention of Cruelty to Animals.

Anyone with information about the case can contact Inspector Gavin McEachern confidentially at (415) 553-7904 or the anonymous tip line at (415) 575-4444.

[Original story published July 30]:San Francisco police are investigating a death in the Castro District. According to Lieutenant Mike Stasko, head of the homicide unit, officers responded to a Castro Street flat Tuesday, July 28 after receiving an anonymous phone call at about 6:30 p.m.

They located an adult male who had been dead for about a week.

Stasko said the medical examiner's office is in the process of positively identifying the man and determining the cause of death.

Stasko said there had been two or three people living in the residence, but he didn't know if the dead man was one of them. He said the residents had not been seen in "a few days," and no one else was in the flat.

The flat was believed to be located at 98 Castro Street, which is north of Market Street at 14th Street. Stasko said that other media have reported that address, which he said was "not inaccurate."

However, he would not confirm that information directly.

"We don't put that out until the investigation gets more going," he said.