Washington ? Dead: 10. Tips: more than 138,000. Reward: $50,000 at first, then $500,000.

Lives changed forever: countless.

The three weeks in which metropolitan Washington lived in the cross hairs of a sniper’s scope are over, but the numbers the drama produced describe a season of fear.

In its wake, prosecutors from at least seven jurisdictions including Montgomery, Ala., where the arrested men are suspects in a Sept. 21 killing are deciding how to proceed.

More than 1,000 federal, state and local law enforcement officers banded together in a hunt that covered Maryland, Virginia, the District of Columbia and eventually the entire country.

Two suspects: John Allen Muhammad, 41, and John Lee Malvo, 17. The search: 22 days. Bullets fired: at least 14 taking 10 lives, wounding three, shattering a window. The bullet caliber: .223.

Rifles confiscated from Muhammad’s vehicle: one, reportedly an XM-15. Number of XM-15s sold annually by Bushmaster Firearms Inc.: 50,000. Retail price: $900 to $950.

Sniper communications: A tarot card, two letters, possibly several phone calls to police, definitely one to a Virginia priest. Six is the number of times Montgomery County, Md., Police Chief Charles Moose publicly addressed the sniper.

A day after the Oct. 14 fatal shooting of Linda Franklin, 47, of Arlington, Va., the assembled task force received almost 11,000 tips from callers. At its busiest, as many as 75 people tended the tip line. Wait time for tipsters: up to 30 minutes.

More than 157,000 students in the Richmond, Va., area missed two days of classes after the sniper wounded a 37-year-old man in suburban Ashland on Oct. 19.

Crime scenes: Four gas stations, four parking lots, one auto dealership, one bench, one bus, one craft store, one school, one street corner.

Vulnerable: metropolitan Washington’s more than 4 million people. Pumping gas, loading packages into a car, mowing the lawn: among suburban routines once considered tedious.

Peapod, a grocery delivery service, told Washington-area customers its services were booked a day, or even two, ahead of time. “You may want to reserve a delivery time in advance in order to get the most convenient time for you,” read a note on its Web site.

At least one area town council voted early last week to “strongly discourage” trick-or-treating on Halloween.

“It’s back on,” said Douglas Miller, town manager at La Plata, Md., after the suspects were arrested. “I told my wife she better go out and buy some candy now.”

The sniper killed one person in the District of Columbia, among more than 20 other murders in October in the nation’s capital. In Montgomery County, Md., which had six sniper victims, there had been one other murder in the month. Fairfax County, Va., the scene of one fatal sniper attack, had no other murders.

The FBI’s most recent statistics for nationwide sniper attacks is 2000. In that year, the bureau recorded eight a number the Washington area sniper topped in three weeks.

Between 75 percent and 80 percent of serial murder cases eventually are solved, according to Eric Hickey, professor of criminal psychology at California State University, Fresno, and an expert on serial killers.

“The vast majority of murders are done by people that you know,” Hickey cautioned. According to 2000 FBI statistics, that is more than 15,000 annually.