Two San Francisco Police Department officers are under investigation: One for sexual assault, the other for interfering with that investigation.

SFPD exclusively confirmed to NBC Bay Area Monday they were investigating an allegation of sexual assault by an off duty officer that took place earlier this month. SFPD is also investigating whether another officer tipped off the suspect about the investigation, a spokesperson for San Francisco police said.

An SFPD spokesperson told NBC Bay Area police are working with the district attorney to investigate criminal allegations of sexual assault against the off-duty police officer.

Police are saying little about the assault and offering very little information about the alleged interference in the investigation by another officer, except to say they're "looking into everything, both administratively and criminally."

But an SFPD search warrant regarding the alleged interference says much more.

According to the warrant, a woman came to SF General Hospital on Aug. 7 saying she was suffering from injuries sustained during a sexual assault that took place five days ago. That night she refused to talk to responding officers, the warrant says. But two days later, she did talk, and identified the suspect, an acquaintance and a police officer, from a photo lineup.

According to the warrant, both the victim and the suspect said they went to the woman’s house in the Sunset District and drank heavily, with the woman "consuming 5-7 drinks in the first half hour" -- all hard liquor. Then the pair went to the woman's bedroom, where she says they had sex despite her saying: "no I don't want to," the warrant says.

The officer told investigators he was quote "hammered." so drunk, in fact that he doesn't remember anything.

The warrant also alleges that a fellow officer at the Taraval Station, and friend of the accused, compromised the investigation.

The search warrant requests approval for investigators to seize the cell phone of the officer who provided that information, saying he "intentionally interfered with a felony sexual assault investigation both by lying to the officers investigating the incident and by contacting the suspect directly to inform him of the progress of the investigation."

The warrant says the information provided from one officer to the other could have allowed the suspect to destroy evidence.