An angry letter found tacked to a tree behind a restaurant where thesniper wounded a man last weekend complained of six failed attempts to reach police, and threatened more killings -- of children in particular -- if millions of dollars were not deposited in a bank account within two days, according to law enforcement sources.

The letter listed half a dozen calls that had been "ignored" by operators answering phones at the command center in Rockville, the Montgomery County police station and the FBI. It even named some of the people who had taken his calls.

They had hung up, the letter stated; that was "incompetent."

"Five people had to die" because of it, the letter said, according to one law enforcement source who has seen a copy of the letter.

The letter gave a deadline of Monday for the money to be deposited in a bank account, the source said. Several people who had seen photocopies of the letter said the amount demanded was $10 million.

The letter warned investigators that if they were more concerned with "stopping" the killings than making an arrest, they should follow the orders precisely, or else there would be "body bags," said a source.

And it ended with an even more ominous postscript, officials said: 

"Your children are not safe anywhere at any time."

The handwritten letter running at least three pages was found sealed and wrapped in plastic in the woods behind a restaurant in Ashland, Va., after Saturday's attack, several sources said. The letter was neatly printed on lined paper and included a number of grammatical errors, including sentence fragments and misspellings, said sources.

Sources said the letter also included a phrase written on a Tarot card left at the scene of the shooting in Bowie on Oct. 7: "I am God."

The discovery of the letter, which police are convinced was written by the sniper who may have killed his 10th victim yesterday, was the impetus for an extraordinary series of veiled public messages to the killer delivered by Montgomery Police Chief Charles A. Moose.

Moose appeared before cameras five times in 48 hours to deliver explicit if sometimes cryptic messages to the man he believes is thesniper -- appearances that followed a series of missed opportunities to communicate.

The letter was found sometime after the Saturday night shooting of a traveler who was hit once in the abdomen as he walked with his wife to their car behind the Ponderosa Steakhouse off Interstate 95 in Ashland, just north of Richmond and 80 miles south of Washington.

It is unclear on what day the sniper began his attempts to call authorities.

One law enforcement official said the man believed to be the attacker failed to get through at least three separate times.

A follow-up call went through, but an FBI trainee who answered the phone did not recognize the call for what it was and cut the conversation short, the official said.

"The individual taking the call did not understand the importance of what was happening," the law enforcement official said. "She pretty much blew him off."

One official described the caller as "extremely angry." The caller, he said, used such phrases as "Just shut up and listen," or "Hear me out," or "I am God," or "I'm in charge."

There was some delay in reacting to the letter because it was sealed and analysts were checking it for evidence, sources said.

When officials finally opened the letter, they found a telephone number that the writer said police would receive a call on, at a specified time Sunday, sources said.

Investigators soon discovered that there was a problem with that phone number, and it took them more time as they tried to straighten it out.

Before the officials had finished their work, the time for the call had passed, several sources said.

So at 7:10 p.m., Moose made the first of his five public appeals to the attacker: 

"To the person who left us a message at the Ponderosa last night, you gave us a telephone number. We do want to talk to you. Call us at the number you provided."

Monday morning, a person police believe to be the sniper called again, according to sources. This time police traced it to telephones in the vicinity of an Exxon station in suburban Richmond.

Police dispatched a SWAT team to secretly watch the area. By about 8:30 a.m., an undocumented worker pulled a white minivan up to the phone and started making calls. Another man, also a laborer in this country illegally, was waiting nearby.

Some minutes later, local police decided to move in and grab both men, in a scene that was carried on cable news networks and for a short time provided hope of a break in the frustrating case.

About this time, investigators in Rockville were struggling to understand the message the caller had left that morning, officials said. It was a tape-recorded message played into the phone, sources said, and parts of it were unintelligible.

At 10 a.m., Moose again went before the cameras with a plea for more time to respond: 

"We are going to respond to a message that we have received. We will respond later. We are preparing that response at this time."

Six hours later, at 4:15 p.m., Moose returned to the cameras and asked for another call. "The person you called could not hear everything you said. The audio was unclear and we want to get it right. Call us back so that we can clearly understand."

At 6 a.m. yesterday, a Montgomery County bus driver was fatally shot in Aspen Hill, not far from where the string of shootings began Oct. 2. Authorities believe the slaying was committed by the sniper.

Sometime before 4:40 p.m., police received another communication.

At 7:15 yesterday evening, Moose addressed the sniper again.

"In the past several days you have attempted to communicate with us. We have researched the option you stated and found that it is not possible electronically to comply in the manner you requested. However, we remain open and ready to talk to you about the options you have mentioned. It is important that we do this without anyone else getting hurt. Call us at the same number you used before to obtain the 800 number you have requested. If you would feel more comfortable, a private P.O. box number or another secure method can be provided. You indicated that this is about more than violence. We are waiting to hear from you."