San Francisco's recently elected sheriff allegedly mistreated his wife on two separate occasions last year, and told her he would attempt to gain custody of their young son because he was "very powerful," according to court documents filed Tuesday.

Sheriff Ross Mirkarimi was charged Friday with one count each of domestic violence battery, child endangerment and dissuading a witness. Prosecutors say those charges are related to a volatile New Year's Eve incident with his wife.

According to an arrest warrant affidavit, Mirkarimi's wife Eliana Lopez appeared in a Jan. 1 videotape in which she discussed details about that confrontation and another incident earlier last year.

In the footage shot by a neighbor, Ivory Madison, Lopez is crying and visibly upset about the couple's run-in the day before, according to the document.

Lopez points to a bruise on her right bicep where she said Mirkarimi grabbed her, the affidavit states.

"This happened yesterday," Lopez tells the camera. "Two times in 2011, and this is the second time this is happening."

"I told Ross I want to work on the marriage -- we need help," Lopez continues, according to the document. "I (have) been telling him we need help, and I'm going to use this just in case he wants to take Theo away from me because he ... said that he is very powerful and he can do it."

Lopez, a former Venezuelan telenovela star, married Mirkarimi after having their first child in 2009.

Lopez said the couple and their 2-year-old son, Theo, were driving to lunch on New Year's Eve when she asked Mirkarimi if she could take a trip to visit her family in Venezuela after he was sworn in as sheriff on Jan. 8, Madison said, according to the affidavit.

Lopez told her Mirkarimi then started to scream expletives at her, saying "you are trying to take Theo away from me!"' Madison told the police investigators in a follow-up interview on Jan. 11.

Lopez told Madison that Mirkarimi then turned the car around and said he wasn't taking them to lunch, according to the document.

Lopez said Mirkarimi then told his wife "something to the effect that she didn't deserve to eat," Madison said.

Once home, voices "became louder," Madison said Lopez told her. Mirkarimi "continued to be verbally abusive and physically abusive" and the incident escalated to the point he was "pushing, pulling and grabbing" Lopez, the affidavit said.

"Look what this is doing to our son, look what you are doing to our son, please stop," Lopez told Mirkarimi, according to Madison. Lopez then ran out of the home, screaming, "Do you want me to call (the) police?"

The couple's son was outside, also screaming and crying, and Mirkarimi came out, apologizing profusely and asking his wife to "please come back in the house, please come back in the house," Madison said Lopez had told her.

Madison later said that when Lopez was talking to her, Mirkarimi called Madison's house looking for his wife and had told Lopez not to tell anybody. Madison said Lopez told him, "I'm going to tell people and I'm going to leave the house and then he looked scared."

Police initially went to Madison's home on Jan. 4 and found Lopez leaving. The affidavit said Lopez simply pointed to Madison, saying she was the one investigators should talk to because she had called them.

Madison then told them what Lopez had relayed to her but would not surrender the videotape. Police later obtained it through a search warrant.

Police said they contacted Lopez by phone on Jan. 5. Lopez said said she was "very well and doing fine" and told them she did not want to be interviewed. Lopez's lawyer, Cheryl Wallace, later told police she would not let Lopez speak.

Police said they also tried to interview Mirkarimi at least four times through his attorney, Robert Waggener, but the sheriff wasn't made available, the affidavit said.

Waggener did not return repeated calls for comment on Tuesday.

Last week, district attorney investigators located another neighbor who said she saw Lopez on Jan. 4 and said Lopez described Mirkarimi as "going ballistic." The neighbor said Lopez had also told her it was the second time Mirkarimi had been abusive toward her and that the first incident had occurred in March.

Lopez told this neighbor that she had locked Mirkarimi out of the house during the New Year's Eve confrontation and threatened to call police, the affidavit said.

"At some point, Ross Mirkarimi grabbed the victim's arm and that's how the bruise happened," the neighbor told investigators. The inspector said the second neighbor described the bruise as "pretty big."

The couple's son, according to the neighbor, told his mother that: "Daddy made boo-boo on mommy's arm."

A former city supervisor, Mirkarimi, 50, is scheduled to be arraigned Thursday afternoon. He has vowed to remain in office while he fights the charges.

Mirkarimi was booked at San Francisco County Jail, but was released on $35,000 bail.

San Francisco Mayor Ed Lee has the authority to charge Mirkarimi with official misconduct and suspend him from office, according to the city's Ethics Commission.

Lee did not immediately respond to a request for comment about the new evidence on Tuesday. Police would not comment on Tuesday, citing an ongoing investigation.