Two people in dark clothes follow you for several blocks. It's after midnight. You look back several times at them. They say nothing, but they continue to follow. What to do? Well, don't even think about menacingly gripping that pocket knife you're carrying to scare them off. They could be undercover cops conducting a training exercise.

A Kensington man was found guilty of criminal threatening for holding an open pocket knife at his side while asking two people who were walking behind him at midnight, "Why are you following me?"

The pair walking behind Dustin Almon, 28, of 27 Wild Rose Lane, were state Liquor Enforcement cops, both in plain clothes without any indicators that they were members of law enforcement, according to testimony during a Thursday Portsmouth District Court trial. Both were also carrying concealed handguns and Tasers, they testified.

One of them, Officer Anthony Cattabriga, said he was walking behind Almon on Chapel Street on Nov. 8, 2008, when Almon turned around three times to look at him and a new officer he was training. It was dark and Almon was twenty feet away when he displayed a knife with a two-inch blade the third time he turned around, said Cattabriga.

"He pointed it down by his side," the liquor officer testified, while demonstrating with Almon's seized pocket knife.

When he responded by yelling "police," Almon folded the knife, clipped it to his belt and complied with all subsequent police orders, Cattabriga testified.

Almon was initially arrested on a charge of disorderly conduct, but the charge was later upgraded to criminal threatening with a dangerous weapon.

"I feared for my safety," Cattabriga said from a District Court witness stand.