The phone calls to several Honolulu taxpayers came at 2 and 3 a.m., and they were collect. But they bore good news: The U.S. Internal Revenue Service computers had malfunctioned and the government owed the taxpayers additional refunds.

It was too good to be true, and in fact it wasn't true, and some of those who were called complained. The IRS brought its investigatory resources to bear and staked out two phone booths from which it was determined the calls to Hawaii -- and similar ones to Albany, N.Y., and Las Vegas, Nev., Atlanta and Hollywood -- had been made.

The booths, located with the help of the phone company, were at Bowie High School and a grocery store in the Bowie area. IRS agents staked out both booths and last week apprehended one suspect as he took a call from an agent posing as one of the taxpayers. They also snapped his picture with a telephoto lens. Soon two other suspects were rounded up.

They are youths aged 15 and 16, according to the IRS, and the whole thing was a prank. IRS spokesman Dominic LaPonzina said the calls were made at random, starting in late May, and that the youths left the taxpayers with callback numbers and asked for nothing except names, address and Social Security numbers.

The three were released in their parents custody without formal charges being filed.

LaPonzina said IRS agents never make collect calls, would not ask for information about a taxpayer (they already have it) and seldom call outside regular business hours. He also said conviction for impersonating an IRS agent carries a maximum penalty of three years in prison and a $1,000 fine.