Authorities recover pressure cooker lid from Boston Marathon bombings

BOSTON (AP) — Authorities investigating the

deadly bombings at the Boston Marathon have recovered a piece of circuit


that they believe was part of one of the explosive devices, and

also found the lid of a pressure cooker that apparently was

catapulted onto the roof of a nearby building, an official said


A law enforcement official briefed on the

investigation confirmed to The Associated Press that authorities have


what they believe are some of the pieces of the explosive devices.

The official spoke on condition of anonymity because this

person was not authorized to publicly discuss evidence in the

ongoing investigation.

A person close to the investigation previously told AP the bombs consisted of explosives put in 1.6-gallon pressure cookers,

one with shards of metal and ball bearings, the other with nails.

Also Wednesday, a doctor at Boston Medical Center said two patients, including a 5-year-old child, remain in critical condition

there. Dozens of others have been released from hospitals around Boston.

Law enforcement agencies pleaded Tuesday for

the public to come forward with photos, videos or any information that


help them solve the twin bombings that killed three people and

wounded more than 170 a day earlier. Investigators circulated

information about the bombs, which involved kitchen pressure

cookers packed with explosives, nails and other lethal shrapnel

— but the FBI said nobody had claimed responsibility.

"Someone knows who did this," Richard DesLauriers, FBI agent in charge in Boston, said at a news conference where he detailed

the type of clues a bomber might have left. "Importantly, the person who did this is someone's friend, neighbor, co-worker

or relative."

President Barack Obama branded the attack an

act of terrorism but said officials don't know "whether it was planned

and executed

by a terrorist organization, foreign or domestic, or was the act

of a malevolent individual." Obama plans to attend an interfaith

service Thursday in the victims' honor in Boston.

Scores of victims of the Boston bombing

remained in hospitals, many with grievous injuries. Doctors who treated

the wounded

corroborated reports that the bombs were packed with shrapnel

intended to cause mayhem. In addition to the 5-year-old child,

a 9-year-old girl and 10-year-old boy were among 17 victims listed

in critical condition.

The trauma surgery chief at Boston Medical Center says most of the injuries his hospital treated after the marathon bombings

were to the legs.

"We have a lot of lower extremity injuries, so I think the damage was low to the ground and wasn't up," Dr. Peter Burke said.

"The patients who do have head injuries were blown into things or were hit by fragments that went up."

Dozens of patients have been released from hospitals around the Boston area.

At Massachusetts General Hospital, all four amputations performed there were above the knee, with no hope of saving more of

the legs, said Dr. George Velmahos, chief of trauma surgery.

"It wasn't a hard decision to make," he said Tuesday. "We just completed the ugly job that the bomb did."

An intelligence bulletin issued to law enforcement includes a picture of a mangled pressure cooker and a torn black bag that

the FBI said were part of a bomb that exploded during the marathon.

DesLauriers said cooperation from the

community will play a key role in the investigation. He said the range

of suspects remained

wide open, but by midday Tuesday more than 2,000 tips had been


The bombs exploded 10 or more seconds apart, tearing off victims' limbs and spattering streets with blood. The blasts near

the finish line instantly turned the festive race into a hellish scene of confusion, horror and heroics.

The blasts killed 8-year-old Martin Richard,

of Boston, and 29-year-old Krystle Campbell, of Medford. The Shenyang


News, a state-run Chinese newspaper, identified the third victim

as Lu Lingzi. She was a graduate student at Boston University.

Officials found that the bombs in Boston consisted of explosives put in ordinary, 1.6-gallon pressure cookers, one with shards

of metal and ball bearings, the other with nails, according to a person close to the investigation who spoke on condition

of anonymity because the probe was still going on.

Both bombs were stuffed into black bags and left on the ground, the person said.

DesLauriers confirmed that investigators had found pieces of black nylon from a bag or backpack and fragments of BBs and nails,

possibly contained in a pressure cooker. He said the items were sent to the FBI laboratory at Quantico, Va., for analysis.

Pressure-cooker explosives have been used in international terrorism, and have been recommended for lone-wolf operatives by

al-Qaida's branch in Yemen.

But information on how to make the bombs is readily found online, and U.S. officials said Americans should not rush to judgment

in linking the attack to overseas terrorists.

Pressure-cooker explosives have been used in

Afghanistan, India, Nepal and Pakistan, according to a July 2010


report by the FBI and the Homeland Security Department. One of the

three devices used in the May 2010 Times Square attempted

bombing was a pressure cooker, the report said.

"Placed carefully, such devices provide little or no indication of an impending attack," the report said.

Investigators in the Boston bombing were combing surveillance tapes from businesses around the finish line and asking travelers

at Logan Airport to share any photos or video that might help.

"This is probably one of the most photographed areas in the country yesterday," said Boston Police Commissioner Edward Davis.

He said two security sweeps of the marathon route had been conducted before the blasts.