NEW YORK (AP) — Investigators cut out a piece of carpet in a painstaking search of a penthouse suite for DNA evidence in IMF chief Dominique Strauss-Kahn's sex assault case, law enforcement officials said Wednesday as he made a new bid to get out of jail.

New York detectives and prosecutors believe the carpet in the hotel room may contain Strauss-Kahn's semen, spat out after an episode of forced oral sex by a hotel maid, the officials told The Associated Press.

Late Wednesday, Strauss-Kahn resigned as managing director of the International Monetary Fund, according to a letter released by its executive board.

In the letter, Strauss-Kahn denied the allegations but said he felt compelled to resign with "great sadness" because he was thinking of his family and also wanted to protect the IMF.

Strauss-Kahn, jailed at Rikers Island since Monday, made a second appeal for bail earlier Wednesday and proposed to be confined to his daughter's Manhattan home 24 hours a day with electronic monitoring. He was set for another hearing Thursday afternoon.

The French politician said in court papers that he had surrendered his passport and wouldn't flee the country. "I do not intend to leave the United States of America without the permission of the New York Court," he said.

In addition to examining the Sofitel Hotel suite for further potential DNA evidence, investigators were looking at the maid's keycard to determine whether she used it to enter the room, and how long she was there, officials said.

One of the officials said that the DNA testing was being "fast-tracked" but that the results could still be a few days away.

The two officials spoke to the AP on condition of anonymity because neither was authorized to speak about the case publicly and because it has gone to a grand jury.

The maid, a 32-year-old immigrant from the West African nation of Guinea, told police that the 62-year-old Strauss-Kahn came out of the bathroom naked, chased her down, forced her to perform oral sex on him and tried to remove her underwear before she broke free and fled the room.

The AP does not identify alleged victims of sex crimes unless they agree to it.

Police Commissioner Raymond Kelly declined to comment Wednesday on the details of the evidence-gathering but said results of any DNA and other testing have not yet come back. He said the detectives investigating the case found the maid's story believable.

"Obviously, the credibility of the complainant is a factor in cases of this nature," Kelly said. "One of the things they're trained to look for, and what was reported to me early on, was that the complainant was credible."

One of Strauss-Kahn's attorneys, Benjamin Brafman, said at his client's arraignment this week that the forensic evidence "will not be consistent with a forcible encounter." That led to speculation the defense would argue it was consensual sex.

The woman's lawyer, Jeffrey Shapiro, has dismissed suggestions from some of Strauss-Kahn's defenders that she made up the charges or tried to cover up a consensual encounter.

In court papers filed Wednesday, Strauss-Kahn's attorneys proposed posting $1 million cash bail and confining him to the home of his daughter, Camille, a Columbia University graduate student, 24 hours a day with electronic monitoring.

Strauss-Kahn "is a loving husband and father, and a highly regarded diplomat, politician, lawyer, politician, economist and professor, with no criminal record," his attorneys said in court papers.

The attorneys had proposed similar conditions at an earlier bail hearing but added the promise of home detention Wednesday. A judge denied Strauss-Kahn bail Monday, sending him to an isolated wing of Rikers Island.

The motion for bail also laid out a more precise timeline for Strauss-Kahn's movements while arguing he never tried to flee: It says he checked out of the hotel at 12:28 p.m., went to a lunch appointment a few blocks away at 12:45 p.m. and went to the airport afterward.

"Prior to the flight's departure, Mr. Strauss-Kahn contacted the hotel at which he had been staying in New York to inquire about a cell phone he had left at the hotel," it added. "In a conversation with hotel security, Mr. Strauss-Kahn voluntarily disclosed that he was at John F. Kennedy International Airport and was scheduled to depart for France at 4:40 p.m."

Police on Wednesday offered their own timeline for their response starting with a 911 call at 1:32 p.m. from hotel security saying an employee had been sexually assaulted by a guest. Officers arrived by no later than 1:45 p.m. and summoned paramedics and special victims detectives to the scene, they said.

Manhattan prosecutors didn't immediately comment on the bail motion. The hearing was set for 2:15 p.m. Thursday. Another hearing had been set for Friday, the deadline for prosecutors bring an indictment, agree to a preliminary hearing or release Strauss-Kahn.

Strauss-Kahn is one of France's highest-profile politicians and was seen as a potential candidate for president in next year's elections. His arrest shocked France.

The scandal comes at a critical moment for the International Monetary Fund, which is trying to shore up teetering economies in Europe. The IMF is an immensely powerful agency that loans money to countries to stabilize the world economy. In exchange it often imposes strict austerity measures.

Defense lawyers can raise the issue of bail as many times as they like, and it's common to make new proposals and try again after a client gets high or no bail, said Stuart P. Slotnick, a New York defense lawyer not involved in the Strauss-Kahn case. Such attempts can succeed if a judge is persuaded that new information reduces the perceived risk that the person won't come back to court if released.

Living elsewhere is often seen as raising that risk, but it's not insurmountable, Slotnick said.

In a case like Strauss-Kahn's, bail "is not going to be a slam-dunk, but if they can convince the judge that he's not a risk of flight, that he's going to come back, then he'll get bail," Slotnick said.