UPDATED 01/10/12 11:12 a.m.

PLAINFIELD, Ill. (CBS) — Authorities and neighbors are worried that a serial arsonist is targeting a block on Plainfield, after several suspicious fires were set in cars on just one block.

As CBS 2’s Susanna Song reports, the fires started in cars, and grew from there in some cases.

In two cases, the torched cars were inside a garage, and the fire spread to the homes. Police say they have reason that the same person or people are responsible for the fires – all set since Christmas Day in the 16700 block of Hazelwood Drive.

Tammy Triner is living a nightmare. All the fires happened right near her home.

Her voice choked up, Triner said she was “devastated, scared for our neighbors. We just hope that they catch them really soon. We’re on no sleep. We’re just very scared.”

The first vehicle was torched on Christmas Day. It remains parked in the driveway where it was destroyed, but it remains charred beyond recognition.

Down the block in the same Arbor Creek subdivision, a car inside a garage was set ablaze, and the entire house burned. The house is now boarded up, and uninhabitable.

Neighbors captured photos of that fire on Sunday morning.

“We heard screaming, and someone was honking their car horn. A neighbor ran up to get us out of the house and pull my mom down the stairs, and we ran out just so scared that ours was going to go up as well,” Triner said.

Police believe someone walked into the open garage and set the car on fire. Flames then spread throughout the house.

“They’re devastated. They have to try to find a new place to live,” Triner said.”We’re just thankful that everybody made it out alive.”

On the same morning, two other neighbors woke up to find that their cars were also on fire.

Plainfield police Sgt. Mike Fisher calls it a crime of opportunity.

“The vehicles have been unlocked, so make sure everybody knows that one of the best ways to prevent this is to keep your cars locked; keep your garage doors shut,” he said.

All five vehicles were unlocked when they were set on fire.

Police are stepping up patrols and talking with a couple witnesses. They say they have several leads.

It is unclear why the affected block was been targeted in particular.