At 9:50 a.m. Wednesday morning, officers arrested 27-year-old Giselle Diwag Esteban in Union City for the suspected murder of Michelle Le, though investigators were still unable to confirm that she had been killed.

Le, 26, disappeared on May 27 from Kaiser Permanente Hayward Medical Center during a nursing class that evening. Le's car was found the next morning around 9 a.m. parked about half a mile from the medical center.

Her disappearance led to a massive search campaign, organized by her family, who has also offered a $100,000 reward for her return or for information on her whereabouts.

“[This] really has robbed us of our lives,” said Michael Le, the victim's brother, at a press conference Wednesday announcing the arrest.

Police had classified the case as a homicide back in June but her family held out hope for her safe return.

A friend of Le's from her high school days in San Diego, Esteban was named a person of interest in the case by investigators back in June.

Esteban had been reported saying that she openly hated Le for stealing her boyfriend, but had nothing to do with Le's disappearance. Investigators had interviewed her multiple times and searched her apartment since Le was reported missing, but didn't press charges until Wednesday.

At a press conference Wednesday afternoon, Hayward Police Lt. Roger Keener said that it wasn't one piece of evidence that led to Esteban’s arrest, but a combination of it, including DNA and surveillance video.

He said investigators found bloodstains in Le's vehicle, and it was later determined that the blood was hers. Then when police served a search warrant at Esteban's house on May 29, they found a pair of athletic shoes, one of which contained Le's DNA.

Keener also said footage from security cameras at the Kaiser Permanente parking structure showed that Esteban was present around the time of Le's disappearance.

Additionally, he said, evidence found inside Le's car indicated that Esteban had been in the vehicle, and that cellphone records show Le and Esteban had traveled along the same path leaving the area just after Le's disappearance.

Keener did not discuss a possible motive in the case.

"We could speculate as to the motive, but it may only be answered by Esteban herself," he said.

Esteban has a history of violence that was documented in police and court records.

Cole Gabaldon, a former boyfriend who lives in San Diego, had told the press Esteban was quick to anger when interviewed back in June.

"She has a really really short temper and when she flies off the handle she really flies off the handle," said Gabaldon. "She got up and had a leg on either side of me. She sat on my chest and she was strangling me."

One notable case is the restraining order filed against her by Scott Marasigan, the father of Esteban's child, on May 24, which was three days before Le was last seen. According to records, the order was filed to prevent domestic violence.

Neighbors told KTVU that ex-boyfriend lives in Fremont house with his parents. Court documents showed he has custody of their little girl, an apparent source of conflict according to neighbor Joel Jose.

"We've always had cops visiting here and, from what I understand, it's because they're keeping the baby from her," said Jose.

Police said they believed that an assault occurred in the parking garage that night in May, but no weapons have been found. Also, because there is no body and Esteban has not admitted to anything, Hayward police still don't know how Le died or what kind of weapon was used.

“We will not consider the investigation complete until Michelle has been found,” said Keener.

The FBI assisted in the investigation by processing evidence at its Menlo Park crime lab.

Stephanie Douglas, special agent in charge of the FBI's San Francisco field office, said Le is the niece of a local FBI employee.

Esteban's arraignment was scheduled for Thursday afternoon in the Hayward Hall of Justice, according to Alameda County Jail records.

KTVU learned late Wednesday evening from a source that wished to remain anonymous that Esteban was at least 7-months pregnant.