01/01 By United Press International While Dallas, Houston, and Austin homicide detectives looked back at a year in which murders declined, the year saw a record set in San Antonio and officers do not know exactly why. Houston police report 506 homicides, the fewest slayings since 1988, when the nation's fourth largest city reported 465. Police statistics show the record is 701 killings in 1981. A spokesman said extra patrols initiated early this year may have had an effect on the number of killings. Police spokesman Rick Hartley said, "We'd like to think it can be attributed to the overtime programs. But as people in law enforcement will tell you, it's very difficult to pinpoint what type of impact the increased patrols have on homicides." Using scheduled overtime, an extra 655 Houston officers were placed on duty during the first few months of the year. Dallas officers were pleased that the number of homicides in the city failed to break 400. The all time high of 501 was set in 1991, but "this year, when all the statistics are in, it will be 390-something," a homicide detecetive said. San Antonio's 1992 murder toll set a record with 221 recorded. The old record was 218, set in 1990. A police official said the previous record was broken on Christmas morning. Capt. Gilbert Sandoval, head of the police department's violent crime division, said, however, the average citizen on the street is not in any immediate danger. Sandoval said, "Most people murdered knew their assailants, and many placed themselves in dangerous situations." He blamed the economy, drugs, alcohol, and gang involvement as some of the reasons the city's murder rate is at a record-breaking high. Police spokesman Lt. Ralph Swearingen said Fort Worth's toll will be lower this year. Swearin gen said, "It's going to be down, probably less than 160, while last year it was 190 plus." He said the record year for Fort Worth was 1986, when the homicide total was more than 200. While Austin is not that much smaller than Fort Worth, only 37 homicides were recorded in 1992. Questioned about the city's low rate, Karen Vallero of the police department's homicide division said, "I've heard comments that we're down because we had a drug task force on the streets for a while, and many murders are drug related." Vallero said the city's all-time high was 84 homicides in 1984.