Police Chief William Bratton of Los Angeles, whose department developed the iWATCH program, calls it the 21st century version of Neighborhood Watch.

Using brochures, public service announcements and meetings with community groups, iWATCH is designed to deliver concrete advice on how the public can follow the oft-repeated post-9/11 recommendation: "If you see something, say something." Program materials list nine types of suspicious behavior that should prompt people to call police and 12 kinds of places to look for it.

Among the indicators:

_If you smell chemicals or other fumes.

_If you see someone wearing clothes that are too big and too heavy for the season.

_If you see strangers asking about building security.

_If you see someone purchasing supplies or equipment that could be used to make bombs.

The important places to watch include: government buildings, mass gatherings, schools and public transportation.

The program also is designed to ease reporting by providing a dedicated toll-free phone number and Internet Web page through which the public can alert authorities. Los Angeles has already begun its toll-free number and planned to put its Web site up this weekend.

The Major Cities Chiefs Association, headed by Bratton and comprised of the chiefs of the 63 largest police departments in the United States and Canada, was expected to endorse iWATCH at its conference in Denver on Saturday as a model for all its communities.

"It's really just common sense types of things," Bratton said.

But American Civil Liberties Union policy counsel Mike German, a former FBI agent who worked on terrorism cases, said the indicators are all relatively common behaviors. And he suspects people will fall back on personal biases and preconceived stereotypes of what a terrorist looks like when making the decision to report someone to the police.

"That just plays into the negative elements of society and doesn't really help the situation," German said.

After the Sept. 11 attacks, the Bush administration proposed enlisting postal carriers, gas and electric company workers, telephone repairmen and other workers with access to private homes in a program to report suspicious behavior to the FBI. Privacy advocates condemned this as too intrusive, and the plan was dropped.

Bratton and LAPD Commander Joan McNamara, who developed iWATCH, say privacy and civil liberties protections are built into this program.

"We're not asking people to spy on their neighbors," McNamara said.

If someone reports something based on race or ethnicity, the police will not accept the report, and someone will explain to the caller why that is not an indicator of suspicious behavior, McNamara said.

The iWATCH program isn't the first to list possible indicators of suspicious behavior. Some cities, like Miami, have offered a public list of seven signs of possible terrorism. Federal agencies also have put out various lists over the years.

**On the Net:

Major chiefs: http://www.majorcitieschiefs.org/