RICHARDSON -- Drones are being used to help law enforcement officers in the search for a missing 3-year-old from Richardson.

The Johnson County Sheriff's Officer and Mansfield Police Department were seen helping Richardson PD with the search for Sherin Mathews in an undisclosed location Tuesday morning.

"We're always hopeful that we can find her alive," an officer said. "But time is our enemy."

Mathews disappeared Oct. 7 after her adoptive father, Wesley Mathews, says he put her in the alley behind their home at 3 a.m. for not drinking her milk. Fifteen minutes later, she was gone. Mathews told police he reported her missing five hours later.

Mathews was arrested and charged with child endangerment, but has since bonded out. He's currently wearing an ankle monitor.

Richardson PD said Tuesday that it will be conducting "several searches" based on leads and information gathered by officers. Some "articles" were found in a field and creek in Richardson, but it's not clear if they are actually evidence at this time, police said.

They added that they will continue to perform "specific searches" like this as tips come in. They searched the same area Friday but want to make sure they didn't miss anything.

Furthermore, police say the family's SUV disappeared for an hour the morning Sherin disappeared. Investigators are asking any neighbors with surveillance video of the vehicle to come forward.

Mathews' parents both remain "uncooperative," according to RPD. Child Protective Services took custody of their other daughter, age 4, shortly after Wesley Mathews was arrested.

Neighbors have left prayers, balloons, and teddy bears in a makeshift memorial for Sherin behind the family's home.

A Facebook event titled Sherin Mathews Search Party was scheduled to take place at 1 p.m. Tuesday near Richland College.