San Francisco District Attorney George Gascon said Wednesday that a decision will be made by the end of this week on whether to charge Sheriff Ross Mirkarimi in an alleged domestic violence case involving his wife.

A neighbor of the couple told San Francisco police on Jan. 4 that Mirkarimi and his wife, Eliana Lopez, had gotten into an argument on New Year's Eve during which Lopez suffered a bruise to her arm, according to a search warrant affidavit.

Lopez allegedly showed the neighbor the bruise, according to the affidavit. During the search, police seized a video camera and iPhone used to exchange text messages about the injury.

Lopez last week denied the allegations, saying in a statement that she has "absolutely no complaint against my husband."

Gascon said after in an unrelated news conference Wednesday that his office is continuing to review the evidence and hopes to decide by Thursday or Friday whether to file charges.

He acknowledged that Lopez is not cooperating with investigators, which "is often the problem of domestic violence cases" that involve victims' significant others.

He said his office handled more than 700 domestic violence cases in 2011.

Mirkarimi was just sworn in as sheriff on Sunday after serving on the San Francisco Board of Supervisors for seven years.