According to the criminal complaints filed against the three new suspects in the Boston bombing case, here's how they became involved in the entire affair.

The information that follows is based on the full complaints for Dias Kadyrbayev and Azamat Tazhayakov, and for Robel Phillipos, which appear to be largely the same, as well as some incoming information on the three new suspects and from the ongoing investigation.

Prior to the bombings
Tsarnaev was the only one of the four that had a dorm room on the campus of UMass Dartmouth, though he apparently also spent time with his brother Tamerlan in Cambridge. Kadyrbayev and Tazhayakov lived together in an apartment off-campus; Phillipos also lived off-campus. All four started at the school in 2011.

Several months before the bombings, Tazhayakov and Tsarnaev went to the banks of the nearby Charles River and set off fireworks.

Monday, April 15 (day of the bombings)
Tsarnaev and his brother allegedly set off bombs along the route of the Boston Marathon.

Wednesday, April 17
In the afternoon, Kadyrbayev drove to Tsarnaev's dorm room, texting and asking if he would come down. Tsarnaev had given himself a haircut. They talked for a while, then Tsarnaev went back up to his dorm room.

Thursday, April 18 (pictures of suspects released)
After attending a class in the afternoon, Tazhayakov got a ride home from Tsarnaev, who dropped him off at about 4 p.m. Shortly after 5 p.m., police released photos of the bombing suspects.

At some point after that, Phillipos called Kadyrbayev, who was driving home from Boston, and suggested he turn on the TV when he got home because one of the suspects looked like Tsarnaev. Between 8:43 p.m. and 8:48, Kadyrbayev then texted Tsarnaev, telling him he looked like the suspect. Tsarnaev replied, "lol," then texting other comments Kadyrbayev assumed were jokes, like "you better not text me" and "come to my room and take whatever you want." It's worth noting that there is no mention in the complaint of Tsarnaev calling his friends and asking them to hide evidence, as had been reported.

At about 9 p.m., Tazhayakov was shopping when he got a text from Kadyrbayev reading, "Have you seen the news?" Kadyrbayev told him that Tsarnaev was pictured by the FBI. Tazhayakov returned to their apartment, and Kadyrbayev showed him the images on CNN. Kadyrbayev texted Phillipos at about 9 p.m. and told him to "go to Jahar's room."

The three met on campus (according to Kadyrbayev, this was as early as 6 p.m., though that seems unlikely) and went to Tsarnaev's dorm. Before the entered, Kadyrbayev showed Tazhayakov the text he'd received from Tsarnaev saying "take whatever you want." At that point, Tazhayakov assumed he would never see Tsarnaev alive again.

Tsarnaev's roommate (who isn't named) let them in, saying that Tsarnaev left a few hours prior. The three watched a movie, and then noticed a backpack that contained fireworks from which the explosive powder had been emptied. Phillipos described the tubes as "approximately seven tubular fireworks, approximately 6 to 8 inches in length." Kadyrbayev decided to remove the backpack "in order to help his friend Tsarnaev avoid trouble." He took the laptop, too, because he didn't want the roommate to think "he was stealing or behaving suspiciously" by only taking the backpack. Kadyrbayev also found a jar of Vaseline which he thought Tsarnaev had used "to make bombs."

The three went to Kadyrbayev and Tazhayakov's apartment with the laptop and backpack. They watched news reports showing Tsarnaev's image and, in Phillipos' words "started to freak out." Kadyrbayev and Tazhayakov began talking in Russian, which Phillipos didn't understand. The three decided to throw the items away, again so Tsarnaev wouldn't get in trouble. At about 10 p.m. (according to Kadyrbayev) or 11 (according to Phillipos), Kadyrbayev put the backpack into a black garbage bag and threw it in a dumpster near their apartment. Kadyrbayev says he did this alone. Phillipos says he was napping while it happened.

Friday, April 19 (Tsarnaev is arrested)
(While not listed in the criminal complaint, at some point during the night between the 18th and 19th, Kadyrbayev changed his profile image on VK.com, a social networking site.)

At 6 a.m., the three saw news reports identifying the Tsarnaev brothers as suspects in the bombings. (It was at this point, according to Tazhayakov, that Kadyrbayev threw away the backpack, the contents of which are reportedly pictured above.) That afternoon, Tazhayakov saw a garbage truck come and empty the dumpster.

The FBI interviewed the three suspects on the 19th and 20th.

Saturday, April 20
The FBI continued interviewing the suspects. Phillipos at this point claimed that he didn't remember going to the dorm room — the basis of the charge of lying to authorities that he faces.

Sunday, April 21
Police search Tsarnaev's dorm room. They find BB's, fireworks, and a hat and jacket like those worn during the bombing.

Thursday, April 25
Phillipos is again interviewed by the FBI; he again denies involvement.

Friday, April 26
In another interview with the FBI, Phillipos finally admits to having participated in the visit to the dorm room.

At some point during the day, the FBI retrieved the backpack from a landfill in New Bedford, Massachusetts.

Wednesday, May 1
The three are arrested and charged with obstructing justice. Phillipos is charged with lying to authorities. Stay tuned right here for more.

Photo: The fireworks authorities found after they recovered Tsarnaev's backpack, as pictured in the complaint. (AP)