CBS News reported last night that investigators believe that the unemployed Tamerlan Tsarnaev may have financed his terrorist plot through the sale of marijuana — an interesting occupation for a fanatical Muslim.  The composition of the bomb has come into clearer focus as well.  The triggering device came from a remote-control car, and the fed still think the gunpowder may have come from fireworks.

Most interesting, though, is the acknowledgment that the Tsarnaevs only had one firearm on them during their gunfight with police:

The search through landfills should remind us that bombers need quite a bit of practice in order to get a device that works properly. Even a trained bomber, like the Times Square terrorist, can easily screw one up. That’s one reason why Tamerlan’s six-month sojourn to Dagestan should be interesting to investigators. If Tamerlan wasn’t testing his pressure-cooker devices here, either he was extraordinarily lucky on his first try — or he got training elsewhere. There aren’t that many places in the Boston region where a bomber could test his designs without attracting a lot of notice.

Also, if Tamerlan was selling marijuana to finance his terrorist plot — or even just to make some cash — it might shed a new light on the 2011 triple homicide, whose victims included Tamerlan’s one-time best friend.  Brendan Mess sold pot, too, and homicide detectives assumed that drugs had been the cause of a dispute that got out of hand.  The New York Daily News makes the connection as well:

Friends of the ex-Golden Gloves boxer have openly speculated Tamerlan may have been involved in a grisly triple homicide two years ago involving one of his close friends. The unsolved case continues to stump investigators in the Boston suburb of Waltham, where Tsarnaev’s friend, 25-year-old Brendan Mess, was found murdered Sept. 12, 2011, in his apartment.

Mess, along with two other men, had their throats slit by either an ice pick or knife, and their bodies were covered in marijuana. The attack was made even more bizarre after police said $5,000 was left at the blood-splattered scene.

A couple of points don’t fit, though.  It was just three months later that Tamerlan left for Dagestan.  Why bail out of an operation so soon after getting rid of the competition, if indeed that’s what happened?  Why leave $5,000 behind, too, if you need financing for a terrorist plot — especially cash that couldn’t be easily traced?

The father of the two bombers will fly back to the US this week to claim the elder son’s body, according to a local CBS affiliate.  Anzor Tsarnaev also pledged to cooperate with the investigation:

The Boston Marathon bombing suspects’ father has planned to travel to the U.S. within the next two days, possibly to claim the body of Tamerlan Tsarnaev.

Anzor Tsarnaev told reporters in the Dagestan province of Russia, where he and his wife reside, he would be leaving Thursday or Friday, the Associated Press reported. The mother, Zubeidat Tsarnaeva, reportedly has not decided if she will make the trip; she was charged with felony shoplifting in Massachusetts a year ago, before the family moved overseas.

The father said he would cooperate with the FBI in the ongoing investigation, according to CNN. Federal authorities went to Russia Wednesday for face to face interviews with the parents.

US officials offered to exempt the mother from arrest if she returned for interviews and the trial of her younger son. Zubeidat may return temporarily, but blames the US for all her misfortunes:

The mother of the two Boston bombing suspects told reporters in southern Russia on Thursday that she regretted ever moving her family to the United States, as her husband said he would travel to the U.S. later in the day to see his surviving son.

“Why did I even go there?” Zubeidat Tsarnaeva said through tears after CBS News correspondent Charlie D’Agata asked her if she regretted the move.

“America took my kids away from me,” she declared through tears, saying she wished she had remained in a village in the southern Russian region of Dagestan instead of emigrating to Boston in 2002.

Tsarnaeva was adamant that police arrested her elder son alive and that he died later in custody. Says said she saw video of him on internet, referring to an amateur video which showed a man stripped of most of his clothing being taken into custody on the day of Tamerlan’s death and Dzhokhar’s eventual arrest.

“What have you done to my son? Why did they have to kill him?” the emotional mother asked during the news conference. She was vague when asked who she believed was behind the conspiracy she claims set her kids up.

On that note, let’s give the last word to the editorial board of the Washington Post, via Instapundit, which asks whether the FBI is focused enough on the real bad guys:

LAW ENFORCEMENT agencies can’t be expected to stop every terrorist attack, any more than they can prevent every mass shooting. If, as most investigators now appear to believe, brothers Tamerlan and Dzhokhar Tsarnaev acted on their own with a bomb design downloaded from the Internet, their plot posed a steep challenge to those agencies, including the FBI and Department of Homeland Security (DHS), responsible for detecting threats.

Nevertheless, there are reasons for concern about the two agencies’ performance, based on what is known so far about their tracking of Tamerlan Tsarnaev. The older and more radical brother was first identified as a possible extremist by Russia, which asked the FBI to investigate him in early 2011. Later that year, also after prompting from Russia, the CIA asked that his name be added to a watch list maintained by the National Counterterrorism Center, The Post’s Greg Miller and Sari Horowitz reported. His subsequent departure for Russia in early 2012 resulted in “a ping” to customs officials, Homeland Security Secretary Janet Napolitano told Congress on Tuesday. However, it appears the FBI never learned that Tamerlan had left the country and was not informed when he returned in July. …

As we said, not every plot by terrorists can be detected. Respect for civil liberties means that not everyone who visits a jihadist Web site or is the subject of an inquiry by another government can be placed under permanent surveillance. But it’s worth asking whether the FBI’s methods for identifying and following up on threats need refinement.