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Scattered showers and thunderstorms will continue in our forecast for Tuesday with little change in temperatures. Meanwhile, a new tropical depression has formed in the Gulf. This depression should become a tropical depression Tuesday with landfall near Tampico, Mexico early Wednesday.
CBS: Image may show Boston Marathon bomber
BOSTON (CBS) - Authorities investigating the deadly bombings at the Boston Marathon have zeroed in on an man seen on surveillance video near the site of the attack.
CBS News correspondent Bob Orr reports that authorities have identified at least one person they want to speak with, either as a witness or as a possible suspect.
At the site of what became the second explosion on Monday, surveillance video captured a man wearing a black jacket and gray hooded sweatshirt placing a backpack on the ground while talking on a cell phone, sources told Orr.
While the man was on the phone, the first explosion went off.
CBS News senior correspondent John Miller reports that authorities settled on one individual late Tuesday and are having discussions over whether to go public with identifying the person.
Meanwhile, investigators have found the lid of a pressure cooker that apparently was catapulted onto the roof of a nearby building, a law enforcement source said Wednesday.
The law enforcement source confirmed to CBS News senior investigative producer Pat Milton Wednesday that the lid was found on the top of a building near the attack site.
In the wake of the attack, security was stepped up around the White House and across the country. Police massed at federal buildings and transit centers in the nation's capital, critical response teams deployed in New York City and security officers with bomb-sniffing dogs spread through Chicago's Union Station.
Homeland Security Secretary Janet Napolitano said that the stepped-up security was a precaution and that there was no evidence the bombings were part of a wider plot.
Pressure cooker explosives have been used in Afghanistan, India, Nepal and Pakistan, according to a July 2010 intelligence report by the FBI and the Department of Homeland Security. 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.
The Pakistani Taliban, which claimed responsibility for the 2010 attempt in Times Square, has denied any part in the Boston Marathon attack.
Al Qaeda's branch in Yemen gave a detailed description of how to make a bomb using a pressure cooker in a 2010 issue of Inspire, its English-language online publication aimed at would-be terrorists acting alone.
In a chapter titled "Make a bomb in the kitchen of your mom," it says "the pressurized cooker is the most effective method" for making a simple bomb, and it provides directions.
The tightly sealed pot makes easier-to-obtain but weaker explosives faster and stronger, amplifying the blast and the carnage.
Naser Jason Abdo, a former U.S. soldier, was sentenced to life in prison last year after being convicted of planning to use a pair of bombs made from pressure cookers in an attack on a Texas restaurant frequented by soldiers from Fort Hood. He was found with the Inspire article.
Investigators in the Boston bombing also are 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 bombing.
Boston police and firefighter unions announced a $50,000 reward for information leading to arrests.