WATERVILLE — Authorities put crime-scene tape around the home of a 20-month-old girl who has been missing since last weekend and two of Maine’s top homicide prosecutors were called to the house Thursday as the search for Ayla Reynolds continued for a sixth day.

Waterville Police Chief Joseph Massey insisted that the girl’s disappearance remains a missing-child case, and that “everything remains open and we’re not discounting anything.”

Massey told reporters that the investigation is now focused on an expanded search of the house at 29 Violette Ave.

“That is the last place Ayla was seen. So as you might expect, we’re going to give a lot of attention to that particular house, looking for any clues where she might be or where it would help us to locate her,” Massey said. “We need to go through that as thoroughly as we can, just like we do in any other investigation.”

He said officials from the attorney general’s office, including criminal division chief William Stokes, were at the house, but that was just to give them an opportunity to look at the site.

“We’re at a point where we thought it was appropriate for him to come in and just do a walk-through,” Massey said.

Spokeswoman Brenda Kielty said the visit to Ayla’s father’s home by Stokes and Andrew Benson, another top homicide prosecutor, was “standard protocol.” She declined further comment on the case.

The police chief played down the significance of yellow tape strung about the perimeter of the small property, saying it was “just an additional barrier” to secure the site. He said people shouldn’t read too much into the presence of a state police incident command van parked there, saying it was for the convenience of technicians working at the site.

The investigation continued in other parts of Waterville, including at the airport, where cadaver dogs were brought in, as well as streams and waterways. By Thursday, police had received more than 200 tips from the public, all of which were being followed up, the chief said.

Ayla was living with her father, Justin DiPietro, 24, who reported her missing Saturday morning. DiPietro told police that he last saw her when he put her to bed the previous night. He said she was wearing green pajamas with polka dots and the words “Daddy’s Princess” on them. She also had a soft cast on her broken left arm.

Ayla ended up with her father after child welfare workers intervened while her mother, Trista Reynolds, checked herself into a 10-day rehabilitation program.

The case has drawn expressions of community support and hope that the child will be found safe. More than 60 people, many of them mothers with young children, gathered at a church in Waterville on Wednesday night for a candlelight vigil.

Massey said he believes police have made “significant progress” even through Ayla has not been found.

“There are a lot of things that we’ve eliminated, and that’s just as important as identifying things,” he said.