5-month-old infant Joshua Summeries. (Credit: Zion Police)

5-month-old infant Joshua Summeries. (Credit: Zion Police)

Updated 08/23/13 – 2:55 p.m.

ZION, Ill. (CBS) — Zion police officers were searching a landfill Friday morning, as they continued the search for a missing 5-month-old boy.

“As most of you already know, the sad truth is that our search for Joshua has lead to the landfill,” Zion Police Chief Wayne Brooks said in a message posted on Facebook. “As you can imagine the tedious process of searching a landfill is a tremendously overwhelming and demanding task.”

Joshua Summeries disappeared Wednesday morning, and police have been questioning his mother’s boyfriend as a “person of interest” in the case.

Police said they’ve gathered good leads in the case, but still haven’t found Joshua, who was reported missing around 8 a.m. Wednesday.

“My hope is the baby’s alive. My fear is no, that we’re now in the point of looking at the worst,” Zion Brooks said Thursday.

Joshua’s mother originally told police her son had been kidnapped by a man who grabbed the baby through a window. However, she changed her story, and later said her boyfriend went to quiet Joshua early Wednesday morning, after Joshua had been crying much of Tuesday night, and she hasn’t seen her son since.

Police were sifting through trash at a Zion landfill run by Advanced Disposal.

Crews were using a backhoe to dig through a section of the landfill, as dozens of officers and others stood by in hardhats and orange vests. A cadaver dog was also at the landfill to assist in the search.

On Thursday, Brooks asked local residents to search through their trash cans for possible evidence.

Since Wednesday morning, police have combed over the neighborhood near Joshua’s home, focusing on garbage cans. Authorities have been labeling garbage cans with red or green marks as they check them for evidence.

“We are looking at garbage cans. We’re looking in any place. We’re looking for Joshua … where ever a 5-month-old infant can be found,” Brooks said. “Our hearts got out to that family, but any of us that are parents certainly would feel the same.”

Zion officials delayed the normal Thursday garbage pickup, pushing it back one day, and asked residents to help search their trash for possible clues.

A baby bottle was found Thursday night on the side of the road, just a few blocks from where Joshua was last seen.

Search dog trainer Robert Larson and his yellow Labrador retriever Dexter have joined the search effort on Friday.

He said there’s a reason why police were focusing on the landfill.

“I don’t care how many scents are around, these dogs isolate that cadaver scent, and catalog all these senses in their brain, so he’s looking for a certain scent,” Larson said.

Larson and Dexter helped find the body of Bryeon Hunter, a Maywood boy whose body was dumped in the Des Plaines River earlier this year. Bryeon’s mother and boyfriend allegedly killed him and dumped his body.