Parents are waking up through the night to check on their little girls, sleeping alongside them in their beds and even using heavy furniture to block the windows.

It's all in response to the latest serial predator to stalk the Phoenix area: A brazen man who creeps into homes in the night to abduct and sexually assault young victims.

"Can you think of anything that would be more serious than to have one of your children, who you believe is safe at home and in bed, taken from your home by a stranger and assaulted?" said police Sgt. Jim Markey. "This has got to be one of the more serious crimes that I would say we have worked on."

In a case that has emerged just months after arrests in two separate serial killings cases, police believe this new attacker may have tried at least five times to break into children's' bedrooms at night through a window.

They have linked him to three assaults, all within a five-mile radius in a south Phoenix neighborhood thick with low-income housing.

Authorities have put out fliers and mailers with a sketch of the man in the neighborhoods where they believe he has attacked, and they've gone door to door to warn residents.

"We're afraid," said Blanca Manzanarez, who lives in the neighborhood where the 5-year-old girl was kidnapped. "I used to let my 5-year-old son play outside by himself. Now, I never leave him alone because I'm afraid someone will take him."

The first case came in August, when a man forced open a window and tried to pull out a 4-year-old girl. The girl's older sister awoke and screamed, alerting their mother, and the man fled.

The second incident was in November, when he kidnapped a 5-year-old as she slept in her bedroom. Police believe the man sexually assaulted the girl before dropping her off naked from the waist down on the doorstep of a woman's apartment five miles away.

Markey said the man knocked on the door before leaving the girl, and the woman was able to get a good look at him before he fled.

The third incident occurred in December, when the man broke through the bedroom window of a 13-year-old girl, sexually assaulted her and fled after her screams brought her mother to the room.

Police are also investigating two more cases that bear similarities. One was the sexual assault of a 4-year-old girl inside her north Phoenix trailer. The second happened last month, when a man opened the bedroom window of a 9-year-old girl and began talking to her before he was scared away.

Police believe the man is choosing and watching his victims and their families before he strikes.

Kamelya Rainey said she and her sister have changed everything about their nighttime routine since the attack, including putting a dresser against her 4-month-old nephew's bedroom window at night and sometimes sleeping with him.

"We don't want to take a chance," she said. "We're actually thinking about moving out because we're afraid for the baby. We want to protect him."

The grandmother of the 5-year-old girl who was kidnapped in November said her granddaughter has nightmares about the attack, has become angry, violent, and paranoid, and is seeing a counselor.

"I wouldn't wish this on my worst enemy," said the woman, who asked not to be identified because she lives in the same neighborhood where her granddaughter was attacked. "I just hope they catch him and don't release him. Ever."