Until more can be determined about the cause of a fire early Tuesday in Northampton, residents of neighborhoods east of downtown have good reason to remain alert. Sadly, many are more than alert. They are afraid.

Local police and fire officials are looking into what led a porch at 11 Hancock St. to burn. Catching a break in this case - as in others - depends on more than neighborhood watchfulness.

Public safety officials must step back in to a role they handled well two years ago: expanded fire and crime prevention.

Tuesday's fire at an apartment house caused $75,000 in damage to the structure but injured no one. It is the latest in a string of unexplained recent blazes going back to 2006, when a property at 25 Hancock St. burned to the ground.

The plague of fires was the main subject at a meeting this week of the Ward 3 Neighborhood Association. For residents, this new business is also old business.

After car fires in late 2007, including three in one night suspected of being arson, roughly 50 neighbors gathered with Mayor Clare Higgins and representatives of the police and fire departments. Together, they sorted through the threat that suspicious fires posed to public safety. Police Chief Russell P. Sienkiewicz told the crowd that month that arson cases are tough to solve, since fires consume physical evidence. He said police need breakthroughs like confessions or dramatically new information.

To help police get that information, the mayor asked people in the neighborhood to be vigilant and to report suspicious people and activities.

Two years later, the problem remains. Two more vehicles, both parked on Hawley Street, burned in May and August this year. Another meeting with the mayor and officials may be called.

Causes of recent fires remain unknown, even though a $5,000 reward was offered in one case. Police believe they can explain one area fire, however; in September they blamed a neighborhood resident with starting a fire that burned a pickup truck parked in a driveway on Pomeroy Terrace.

Investigators this week could not find any evidence of an accelerant at 11 Hancock St. But dry leaves nearby might have been used to get a fire going; so far, there is little other plausible explanation.

Thankfully, firefighters reached the Hancock Street fire within five minutes of receiving a call at 12:51 a.m. Police were able to help three tenants, and one dog, to get out safely. The fire was put out in short order.

As they look for breakthroughs today, Northampton police would do well to repeat steps they took in 2007: canvassing the neighborhoods to urge people to keep their cars locked, their porch lights on and their trash secured. It makes sense, also, to post new fliers with a telephone tip line about neighborhood fires.

Also, two years ago, both the fire and police departments increased their visibility in the area. That may well have had an effect, since the frequency of fires dropped, until this year. We'd like to see them back out in the neighborhoods - sending a clear signal that criminal activity that puts so many lives at risk won't be tolerated.