SHIELDED FROM the camera in order to hide their identity, an elderly couple told a television reporter the other night that they were afraid someone was trying to burn them out of their three-story rowhouse. They recalled that, a few days before a blaze mysteriously started in their basement, someone called and asked them to sell their home. They declined; now they aren't sure they made the right choice. They're afraid it may be too dangerous to live in their Capitol Hill home, which they have owned for more than 20 years.

The number of unexplained fires has reached crisis proportions in cities around the country, and Washington is no exception. In the past three years, fires that appear to have been deliberately set have increased an almost unbelievable tenfold in the District. Even harder to accept - without the darkest suspicions - is the number of those blazes that have occurred in older neighborhoods that are changing in ownership and where the cost of homes is rising. There are perhaps as many causes for those fires as there are unsolved cases. Investigations in other cities have uncovered landlords, for example, who saw to it that their residential or commercial property was burned so they could collect insurance - often more money than the property could be sold for. Some speculators hired arsonists to "encourage" homeowners - particularly elderly ones - to sell quickly and cheaply, allowing them to resell quickly and expensively. Burglars often set fires to cover up their crimes. Children too often play with matches. But regardless of the specific reasons, the results are pretty much the same. People - especially those of modest means - increasingly feel that, somehow, somebody is trying to force them out of their neighborhoods.

Although a number of District officials seem to be at least aware of the increase in deliberate fires, there is precious little evidence of the sort of visible concern - or even curiosity - that you would expect. The fire department, for example, doesn't keep track of the pattern of arson in specific neighborhoods, though there is reason to believe that frequent alarms in the same general area are not coincidental. The city's Department of Housing and Community Development doesn't give much attention to blazes that occur in city-owned abandoned buildings, though officials do acknowledge that unexplained fires in empty houses often frighten neighbors into moving. And Mayor Walter Washington has given no visible indication that he is disturbed by the extraordinary increase in suspected arson - or is even doing anything about it.

There are things that he could do. In Seattle, when officials confronted a similar increase in unexplained fires, they found effective ways of dealing with it. Fire and police departments, insurance companies and the media gave public attention to the problem. Residents were encouraged to provide officials with information that could lead to arrests - and confidentiality for informants was guaranteed. With concentrated effort, the number of acts of arson decreased while the number of convictions nearly doubled. Arson was no longer considered an unsolved crime; violators began to realize that they would most likely be caught. What will it take to get the mayor to mobilize a similar public campaign here? A twentyfold increase in the arson rate?