Howard County, fire investigators have arrested a 19-year-old man who they say is suspected of setting 28 fires in his Columbia neighborhood on two nights last October and last week.

John Haren, of 5500 Harper's Farm Rd., has been charged with 18 counts of arson and malicious burning for what one official called "the most serious fires." Investigators say that 10 other arson cases have also been cleared with the arrest.

Meanwhile, residents of the neighborhood where the burning incidents occurred are beginning to relax, after several months of watching each others' houses and searching for clues.

"People in Columbia have become a lot more fire-conscious after all this," said fire dispatcher Charles Lewis yesterday.

The first series of fires occurred on the night of Oct. 13, authorities said. A total of 15 blazes were set, including ones in a carport and under two vehicles.

Then, Friday, 11 more fires were set in the same neighborhoods, dstroying $32,000 worth of property, including the same carport burned previously. Haren was arrested during the day Friday.

Lewis said residents of the areas where the fire occurred teamed up to watch houses when neighbors went ot for the evening and helphed search for evidence after Friday's burnings.

District Court Commissioner Walter Closson denied bail for Haren after his arrest. Haren, who is unemployed, was taken to Springfield State Hospital for psychiatric testing, authorities said.