HAYWARD --

A Union City woman was arrested Wednesday on suspicion of murdering a nursing student who vanished from a Hayward parking garage more than three months ago, police said.

Giselle Esteban, 27, told an interviewer shortly after her old high school friend Michelle Le vanished that she openly hated Le for ruining her relationship with her former boyfriend. She denied having anything to do with the 26-year-old Le's disappearance, but on Wednesday, Hayward police said they think Esteban killed her.

Le was last seen around 7 p.m. May 27 when she went to her car during a break in a clinical lesson at Kaiser Permanente Medical Center on Hesperian Boulevard in Hayward. Police believe that Esteban, Le's former classmate at Mount Carmel High School in San Diego, killed her at the hospital's parking garage.

Le's body has never been found, and police Lt. Roger Keener said at a news conference that investigators don't know how she died. But he added, "There's been nothing in our investigation that supports anybody else's involvement in Michelle's demise, other than Esteban."

Le, who lived in San Mateo, was a student at Oakland's Samuel Merritt University and hoped to become a nurse practitioner like her mother, who died of cancer when Le was a teenager.

Esteban was arrested without incident Wednesday morning at her condominium on Monterra Terrace. Keener did not cite a specific motive for the killing, but did note the interview that Esteban gave to KGO-TV shortly after Le was last seen in which she blamed Le for destroying her relationship with Scott Marasigan of Fremont, her ex-boyfriend and the father of their 5-year-old daughter.

Le's blood was found in her 2010 Honda CRV, which she had parked in the Kaiser hospital's parking garage. The car was discovered a half-mile away the day after she was last seen.

Le's DNA was also found on the bottom of one of Esteban's shoes, Keener said. Security camera footage placed Esteban at the parking garage before and after Le disappeared, and physical evidence confirmed that Esteban was in Le's Honda, Keener said without providing specifics.

Cell phone records show that both women's phones "traveled on a similar path" from the Kaiser hospital to the Niles and Sunol Canyon areas in Alameda County, Keener said.

Marasigan, Esteban's ex-boyfriend, filed court papers shortly before Le vanished in which he outlined Esteban's erratic behavior.

In his request for a restraining order, filed in Alameda County Superior Court on May 24, Marasigan accused Esteban of stalking him and having him followed.

In one incident, Esteban came to his home uninvited and stood outside their daughter's room, he said. When Marasigan's mother asked what she was doing, Esteban said, "I'm messing with your son," he wrote.

Marasigan declined to comment Wednesday.

Police still do not know where Le's body is, and Esteban isn't talking, Keener said.

Esteban is being held without bail at Santa Rita Jail in Dublin and is scheduled to be arraigned today. Law enforcement sources, speaking on condition of anonymity, said Esteban is pregnant.

Police were joined at the news conference by Le's relatives, wearing "Missing" shirts with Le's picture, and FBI agents. Le was the niece of an FBI employee, and the bureau provided technical help in the case.

Le's brother, Michael Le, said his 24th birthday today would be bittersweet without his sister.

"She would always call me and tell me, 'Happy birthday,' and tell me that she loved me," he said, his voice breaking. "I just want to hear her voice so badly, and the only thing I'm going to be wishing for is for her to come back home."