April 22 (Reuters) - Prosecutors charged badly wounded bombing suspect Dzhokhar Tsarnaev in his hospital bed on Monday with carrying out last week's attack on the Boston Marathon. Here are key parts of the criminal complaint:
* Investigators are linking Tsarnaev and his older brother Tamerlan to last Monday's bombings based largely on their resemblance to the suspects identified in photographs and videos of the scene, their alleged admission to the owner of a car they hijacked, and their behavior and possession of weapons and explosions in the days after the attack. The complaint does not say whether investigators have other evidence, such as evidence of the brothers planning the attack.
* The complaint does not discuss possible motives.
* About seven minutes before the first explosion, a man investigators believe is Tamerlan Tsarnaev can be seen in video footage heading toward the finish line where the first explosion would occur, a backpack on his back, the complaint said.
* About four minutes before the first explosion, video footage shows the man investigators believe is Dzhokhar Tsarnaev placing his backpack on the ground at his feet. He stands there for the next four minutes with his cellphone out, apparently taking a photograph at one point, and then apparently making an 18-second phone call. A few seconds after the call ends, the first bomb goes off, and he appears to react calmly while everyone else around him panics.
* Dzhokhar Tsarnaev is seen walking "calmly but rapidly" away from the site following the first blast, now without his backpack, the complaint said. About 10 seconds later, the second bomb explodes where he had been standing.
* Both bombs are described as "low-grade explosives" housed in pressure cookers of the same brand and packed with metal pellets, some of which were "contained within an adhesive material," and nails, the complaint said.
* Three days after the bombing, one of the brothers - the complaint does not say which - hijacked a man's car in Cambridge, hours after officials released images of the suspects. He pointed a gun at the victim, saying: "Did you hear about the Boston explosion?" and "I did that," the complaint said. The brother showed the victim that the gun was loaded, saying, "I am serious." They drove a short distance to pick up the other brother, who got in the back of the car.
* Before the car's owner was able to escape while they were parked at a gas station, the two brothers chatted in a foreign language as they drove, the victim told investigators. They took $45 from him and also can be seen on security camera footage stopping at an ATM and attempting to withdraw money from the victim's bank account.
* A short time later, the brothers threw at least two "small improvised explosive devices" out of the car window as police neared them in nearby Watertown. The car was later abandoned with a "low-grade explosive device" still inside it, the complaint said, and another two unexploded devices were found at the scene of the shootout, as a well as an exploded bomb made of the same brand of pressure cooker and design as used in the marathon bombing.
* After Tamerlan Tsarnaev was pronounced dead at Beth Israel Hospital, FBI agents confirmed his identity with photographs and by taking his fingerprints. Dzhokhar Tsarnaev was carrying identification, including his student ID, at the time of his capture the following evening.
* On Sunday FBI agents found "a large pyrotechnic" while searching Dzhokhar Tsarnaev's dorm room at the University of Massachusetts at Dartmouth. They also found a black jacket and a white hat resembling those worn by the second bomber seen in video footage. (Reporting By Jonathan Allen; Editing by Bill Trott)