Thousands of houses nationwide are part of Project Blue Light, a memorial promoted by the group Concerns of Police Survivors, or COPS. Participants put a blue light in a window or tie a blue ribbon on a wreath.

Pam Sohn created a Christmas display of blue lights adorning her entire house in Washington Court House, Ohio, because her son-in-law, a police officer in California, was killed in the line of duty nearly two years ago.

Pam Sohn, 46, has done considerably more. She has dedicated her whole house to the memory of the man who made her stepdaughter happy.

"He was a guy that you talked to for 20 minutes, and it felt like you had known him your whole life," Sohn said.

Detective Doug Jacobs of Riverside, Calif., was killed Jan. 13, 2001, while responding to a complaint of loud music, according to reports in The Press-Enterprise, a Riverside newspaper. As Jacobs and another officer tried to arrest a man, the man's brother fired. Jacobs, 30, was hit in the face.

The man who fired the gun, Steve Woodruff, is on trial on a charge of murder.

When Doug Jacobs died, the Sohns mourned him. But the blue lights didn't go up last Christmas. It took a visit this year to Washington, during National Police Week, to start that process.

The Sohns went to see Jacobs' name added to a memorial wall. While they were in the nation's capital, the Ohio chapter of COPS invited them to a dinner. Sohn became co-chairwoman of an Ohio COPS event held last month to remember fallen officers. And she has become perhaps the most fervent promoter of Project Blue Light.

Inside her house, Mrs. Sohn has replaced her regular hall light with a blue light. The tablecloths are blue, as are the Christmas stockings and the hand towels. The artificial tree is white with blue ornaments and blue lights.

Tammy Jacobs hasn't yet seen photos of her stepmother's blue creation. But Mrs. Sohn will take some along when she goes to Woodruff's trial early next month.

"I think Tammy will be surprised," she said. "And she'll be proud."