TACOMA, Wash.  — Tacoma police made the grim announcement late Thursday that the body of a Tacoma girl who was the focus of a week-long AMBER Alert has been found.

Twelve-year-old Zina Linnik had been sent down the alley behind her home to bring back some of her siblings, who had been watching neighbors set off July 4 fireworks, police say.

Her father, Mikhail Linnik, heard her scream, found a single flip flop on the ground and saw a boxy gray van driving away. His description of that van eventually led authorities to a man jailed this week on an immigration complaint — and information from that man led them to the little girl's body.

At a brief news conference Thursday night, Police Chief Don Ramsdell said police and FBI agents had found Zina's body at an undisclosed location in Pierce County and that crime scene investigators were combing the area.

The grim news brought "great anguish" to the Linnik family as well as to officers who had worked to find the girl, Ramsdell said.

"Our hearts and prayers are with the Linnik family and we will continue to put forth our best efforts to bring the perpetrator of this senseless and horrific crime to justice," he said.

The tragic news saddened and angered family, friends and community members who spent days searching for the girl.

"I'm just sick," said Michelle Yellada, family friend.  "I was hoping to find her alive, that they would find her alive.  I'm just really heartbroken because I know the family and we see them all the time it's just sad, sad thing for the family."

"I'm so sorry for the family and the people so close to the little girl," said Dave Emery, neighbor.  "It's a tragic loss."

"Personally, the thing that upsets me is that a habitual sex offender should not be on the streets," said Sincere Hankins, Tacoma resident.  "So, whatever he gets coming to him, I think he deserves double."

Police outside the Linnik home Thursday night said the family did not want to make a public comment. They said they were being surrounded by loved ones and are relying on their faith during this time. The family moved from Ukraine about 10 years ago; Zina was one of eight children.

Ramsdell did not identify by name the man whose information led police to the body. At this point, he has only been described as a person of interest. However, the description of the gray van and part of its license plate, glimpsed by the girl's father, led them to a 42-year-old male Thai immigrant who was convicted of incest in 1990.

A search of the home where the man had been staying turned up "girl's undergarments," according to a search warrant return.

The man denied any involvement in Zina's disappearance and said he was not in Tacoma's Hilltop neighborhood July 4, Detective L.J. Wade wrote in an affidavit filed in Pierce County Superior Court in support of the search warrant application.

Investigators and forensic experts from the FBI searched the home on Monday, seizing items including used vacuum cleaner filters, bedding, black plastic sheeting and the undergarments, on which the search warrant return did not provide further details.

The man was later transferred to federal immigration detention in Tacoma because he could face deportation for his 1990 incest conviction, U.S. Immigration and Customs Enforcement spokeswoman Lorie Dankers said earlier this week. But he also has been charged in Pierce County with failing to register as a sex offender, and would face that charge before being deported.

Court records show the man was charged in 1990 with raping a 16-year-old relative. He pleaded guilty to a lesser charge of first-degree incest in exchange for completing 60 months of sexual-deviancy counseling.

Ramsdell took no questions Thursday night. Calls to Tacoma police spokesman Mark Fulghum and the FBI were not immediately returned.

Fulghum said earlier this week he did not know whether the man had obtained a lawyer.

KING 5's Roberta Romero contributed to this report.