For seven years, Julie Digak, manager of Lord Baltimore Cleaners in the Wilde Lake Village of Columbia, had been leaving the rear door unlocked as a convenience for employes arriving for the early morning shift.

However, after attending a seminar sponsored by Howard County police on the problems of burglaries in the area, Digak now insists that employes knock at the front door where she can easily identify them.

Working with merchants such as Digak, the police last week offered a "Target Robbery" seminar as part of a stepped-up campaign to deter holdups and thefts at liquor stores, restaurants, general merchandise stores and bars.

Howard County police currently offer free crime prevention seminars for homeowners and businesses, Gavin said.

However, the Target Robbery program is more intensive, offering shopowners a broad overview of the criminal investigation process, along with tips on how to avoid becoming victims, Gavin said. For example, patrol officers, crime laboratory technicians and detectives are asked to participate in the robbery seminar, he said.

Last year, Howard recorded 1,616 burglaries, up 14.4 percent from the 1,413 in 1985, according to the most recent police statistics available.

Of those incidents last year, 46 were classified by the police as armed robberies. So far this year, there have been 53 armed robberies in the county, three of which were fatal, including the killings of a 20-year-old High's store clerk in Wilde Lake and of well-known restaurateur George Prassos, police detective Stephen Greisz said last week.

Police attribute the rise in property crimes to the county's rapid growth and its proximity to the major metropolitan areas of Washington and Baltimore.

Columbia merchants last week praised the two-hour seminar, which stresses personal safety and includes representatives from the patrol unit, crime lab and detectives section. They discuss the criminal investigation process from the initial call to the arrest and trial of a suspect.

Wanda Ayers, a clerk at the Wilde Lake Pharmacy, filled up several pages of a legal-size pad with notes to share with the store's other 14 employes.

"Knowing what to do is important, especially after {a holdup}, such as not covering up the evidence," Ayers said.

Among the crime prevention tips stressed at the Columbia seminar:

Don't do anything to put yourself in jeopardy. Do exactly as a robber asks.

After a burglar leaves, lock the door so he cannot return.

Do not tamper with the scene Don't leave a clerk alone in a high-volume business, such as a convenience or liquor store.

Improve lighting; it is the cheapest form of security.

Use your sixth sense. If something looks suspicious, call the police.

Make frequent bank deposits of large amounts of money.

Check references of all job applicants. Taking photos of new employes also may deter would-be criminals.