Acting on what they call a strong lead, police have excavated a Texas landfill looking for evidence relating to the disappearance of baby Gabriel Johnson, who has been missing for more than a month.
"Let me say this -- that we do remain hopeful that baby Gabriel is alive," chief of San Antonio Police Department William McManus said at a news conference Tuesday at the landfill.
However, police are running two parallel investigations, McManus said -- one missing persons investigation, and one homicide investigation.
Crews will remove 45 feet of debris and cadaver dogs will be part of the search, McManus said, according to ABC News' San Antonio affiliate KSAT 12.
"We'll begin the arduous task of sifting through layers in the search for possible evidence," McManus said.
Logan McQueary, the baby's biological father, told The Associated Press he was disappointed the case was being treated as a homicide and launched his own search for the boy.
"If you do think you have Gabriel, and you're scared, don't be," McQueary told reporters Sunday. "You can drop him off anywhere or just come forward and say what happened. We're not looking for anybody to get in trouble. All I want is my son back."
McQueary spent the weekend talking with authorities and working with volunteers to hand out flyers door to door.
Last week, investigators said they were "less and less optimistic" Johnson was alive, despite the arrest and interrogation of Tammi Smith, a person of interest in the baby's disappearance.
Neither Smith nor Elizabeth Johnson, the boy's biological mother, who was also arrested, have been helpful in providing information about where the baby might be, Tempe, Ariz., police Lt. Mike Horn said last week. Days after the baby disappeared, Elisabeth Johnson told Gabriel's father she killed the boy. She since claimed to have given the boy to a couple in San Antonio, police said.
Johnson was arrested in Florida and extradited to Arizona where she is in custody.
Smith was arrested on charges of forgery, custodial interference, and conspiracy to commit custodial interference, Tempe police said.
Smith, 37, and her husband, Jack, said they were in talks to adopt Gabriel before he disappeared in December.
Smith was interviewed by police and gave a statement following her arrest, but the information wasn't likely to help the investigation, Horn said.
Investigators do not believe Smith knows where Gabriel is, according to arresting documents. She was arrested for her alleged involvement in a wrongful adoption.
The Smiths were previously named as persons of interest in Gabriel's case. Police served a search warrant on their home, believing the two may be withholding information. Police took their phone records and laptop. Jack Smith is no longer a person of interest in the case, Horn said.
Smith's attorney, Michael Kimerer, said after her arrest that she has always been forthcoming in her meetings with the police.
"When Tammi went and visited the police, she told them everything she knows," he said.
Johnson and McQueary were in the middle of a custody dispute when Johnson fled Arizona with Gabriel before Christmas. She allegedly sent text messages to McQueary, saying she had killed their son and left his body in a trash bin.
Johnson later changed her story and said she gave the baby to a couple she met at random in a San Antonio park. Police have not been able to confirm that that couple exists.