Reports: Brothers used similar bombs in marathon, police showdown

(CNN) -- On Monday, as he remained hospitalized for injuries incurred during a massive manhunt and a pair of shootouts last week, Dzhokhar Tsarnaev heard from his hospital bed his Miranda rights being read, and then he heard read the federal charges now filed against him in connection with the Boston Marathon bombings.

The 19-year-old faces charges of using and conspiring to use a weapon of mass destruction resulting in death, and of malicious destruction of property by means of an explosive device resulting in death.

What follows is a chronology produced by FBI special agent Daniel Genck, who is part of a Boston counterterrorism squad and who based his re-telling of events on crime scene photographs and video, as well information he gleaned from other officers as well as from his own involvement in the case.

Genck said he is not divulging all of the details he has, just what is necessary to establish the following. As told via the criminal complaint:

At 2:38 p.m. on Monday, April 15, roughly 11 minutes prior to the first blast, Tamerlan and Dzhokhar Tsarnaev are caught on camera turning onto Boylston Street, the thoroughfare where the finish line is located.

Tamerlan Tsarnaev is wearing a baseball cap, sunglasses, a white shirt, dark coat and tan pants. His little brother is wearing a gray hoodie, a black jacket and dark pants. He also has a white baseball cap, turned backward on his head.

The pair walks east, toward the Boston Marathon finish line, Tamerlan Tsarnaev in front of Dzhokhar Tsarnaev, wearing a knapsack on his back.

The two are seen standing about a half-block from Forum restaurant, the site of the second explosion, at about 2:41 p.m. A minute later, Tamerlan Tsarnaev begins walking toward the finish line again. He still has his knapsack.

Dzhokhar Tsarnaev begins walking toward the finish line at about 2:45 p.m. He has his right thumb hooked under his backpack strap and there's a phone in his left hand. He stops in front of Forum.

He's near the metal barricades separating spectators from the marathon contestants, standing with his back to the cameras.

"He then can be seen apparently slipping his knapsack onto the ground. A photograph taken from the opposite side of the street shows the knapsack on the ground at (Dzhokhar Tsarnaev's) feet."

Dzhokhar Tsarnaev stays at this location for about four minutes, looking at his cell phone and "once appearing to take a picture with it." About 30 seconds before the first blast, he lifts the phone to his head and speaks for about 18 seconds.

He finishes the call, and the first explosion goes off within seconds. "Virtually" everyone along Boylston turns toward the finish line, "in apparent bewilderment and alarm," but not Dzhokhar Tsarnaev. He appears calm.

"He glances to the east and then calmly but rapidly begins moving to the west, away from the direction of the finish line. He walks away without his knapsack, having left it on the ground where he had been standing.

"Approximately 10 seconds later, an explosion occurs in the location where (Dzhokhar Tsarnaev) had placed his knapsack." Like Tamerlan Tsarnaev's bag, the knapsack is placed along a metal barrier. It's about a block from the first explosion.

Subsequent investigation shows that both bombs used in the marathon attack were "low-grade explosives that were housed in pressure cookers." The pressure cookers contained nails and BBs, and the bombs had "green-colored hobby fuse."

On Thursday, the FBI distributes photos and videos of the brothers, which are widely broadcast by media outlets.

Just before midnight, a man is sitting in his car on a road in Cambridge when a man taps on the passenger-side window.

The driver rolls down the window, and the man lets himself into the car, points a firearm and says, "Did you hear about the Boston explosion? ... I did that." He then shows the driver that his gun is loaded.

"I am serious," the man says before forcing the victim to drive to another location where they pick up a second man.

The armed man takes the driver's keys and sits in the driver's seat, while the kidnapped man moves to the passenger seat. The second man enters the back seat, and he and the driver begin talking in a foreign language.

They begin driving, and the man with the gun demands money. He is given $45 but wants more and demands an ATM card and password. They go to an ATM machine, where the men attempt to get money, before going to a gas station, where the captive man escapes.

Police later locate the stolen vehicle in Watertown, a suburb west of the city, and give chase. As they attempt to elude law enforcement, the Tsarnaev brothers throw two small bombs out of the car. A gunfight ensues, and Tamerlan is severely injured and left at the scene, while his brother escapes.

Police later find the car abandoned with an "intact low-grade explosive device" inside. Federal agents recover two more bombs at the site of the shootout. The bombs resemble those used in the marathon bombings. One even utilizes the same brand of pressure cooker.

On Friday evening, police learn that an individual is inside a covered boat in Watertown. After a shootout, police apprehend the man and search him. He has a university ID card, credit cards and other forms of IDs which say he is Dzhokhar Tsarnaev.

Due to wounds in his head, neck, legs and hand, he is transported to a hospital.

On Sunday, police search Dzhokhar Tsarnaev's dormitory room and recover a "large pyrotechnic" as well as a black jacket and white hat similar to the one Dzhokhar is seen wearing just before the explosions at the marathon.