But those answers won't come quickly, a forensics expert says.
Bosma, 32, a married father of a two-year-old daughter from the Hamilton community of Ancaster, went missing more than a week ago after he accompanied two men on a test drive of the truck he had posted for sale on Kijiji and AutoTrader. On Monday, Hamilton police announced that Bosma was dead.
Retired police detective Kevin Bryan has been watching the case closely. He spent 16 years in York Regional Police's forensics unit. He left the force in 2011 after a 30-year career, and now teaches in Seneca College's police foundations program.
“These are the ones that make you want to go back to work after you retire,” he said.
Bryan is no stranger to crime scenes, and has worked on a number murder cases. He told CBC Hamilton that answers about who killed Tim Bosma and why will come — but it will be a complicated process.
Trying to find answers
“When you get an investigation of this magnitude where there are several different jurisdictions involved as well as several different locations … each one has to be treated as its own individual crime scene, which is quite involved,” Bryan said.
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The Bosma investigation is now largely focused on a farm near Cambridge, Ont., owned by the family of 27-year-old Dellen Millard. Millard was charged Wednesday with first-degree murder in connection to Bosma's disappearance. At least two other suspects are being sought.
The Hamilton police forensic unit has set up a large tent at the rear of the property, and officers are sifting through buckets of material while searching the property on foot and by horseback. Other search warrants are being executed in the case, police have said.
Bryan said he has worked on similar cases where there are as many as a dozen scenes where evidence has been disposed of.
“The secret to good forensic investigations is to link one crime scene to the other,” he said. “But it's very very complicated and it's going to take them some time.”
In these kinds of situations, the lead investigator has to be taken through each individual crime scene to make sure nothing was missed. “And then the stuff all has to be evaluated,” Bryan said. “It can take months before everything is tied together. Sometimes even longer than that.”
The case against Millard will likely take years to get to court because of the time it will take to assemble evidence, Millard's lawyer Deepak Paradkar said. “It's going to be a long time before we get disclosure. It's an ongoing case.”
Bryan said it often takes months to put cases like this together, “So I could see it taking a year or two years before it actually gets before the courts.”
Disposing of evidence?
A police source told CBC News that investigators believe Bosma may have been killed as the result of an attempted carjacking.
The same police source said that Bosma's truck was found with seats missing. A spokesperson for Hamilton police wouldn't comment on this information.
Bryan said in his experience with homicide cases, seats or even whole interiors are sometimes removed to dispose of evidence.
“I've seen homicide investigations where the entire car was gutted if it was used for the commission of the offence,” he said. “But without yet knowing the motive, it's hard to say.”
'Burned beyond recognition'
Bosma's body was found “burned beyond recognition,” Hamilton police said. That adds some challenges to the investigation, Bryan noted.
“A lot of people burn either vehicles or they burn a body to try and get rid of evidence,” he said. “Fire scenes are very often employed to try and destroy evidence such as DNA.”
Police usually identify a body in one of three ways — through dental records, fingerprints or DNA. Fire makes finding a cause of death more difficult, but not impossible, he said.
“It really depends on how much the body was burned,” Bryan said. “I've seen bodies burned to the point that just a skeleton is there … But I've also seen fires where you might not be able to recognize the person, but there's still lots of evidence left there.
“It really depends. Burned beyond recognition is a very open-ended statement.”
Cellphone records 'could be crucial'
Cellphone records could prove integral to figuring out why Bosma was killed, Bryan said. At a Tuesday press conference, Hamilton police revealed that it was Bosma's cellphone that led police to Millard as a suspect.
“It's an investigative tool that is highly used now,” Bryan said. “They can tell you what tower you were bouncing off of and from what geographical area.”
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But just because that data exists, it doesn't mean it's easy to obtain. Bryan said a lot of work has to go into pulling phone records.
“Plus, you're into warrants for quite a few of them — and you don't just get handed a warrant and go do it,” he said, adding that he thinks phone records will “become crucial” to figuring out what happened to Bosma.
“It may take them a few days to track down the warrants and a few days to get those phone records traced,” he said. “I really think some good leads could potentially come out of that fellow's phone records.”
Chasing more suspects
Hamilton police have been tight-lipped about the case, but have said they are looking for at least two more suspects — maybe more. Bryan said in a case like this where a suspect is already is custody, it's likely that officers are already watching other people.
"I'd be really surprised if somebody wasn't under surveillance right now," Bryan said. "Someone is being watched."
Police said they have video footage of a second vehicle following Bosma's truck when he took the two men for a test drive. "He didn't come there with a stranger. Now it's a matter of knocking down the doors of [Millard's] associates," Bryan said.
Tips piling in
Hamilton police have repeatedly said the public's interest in this case has been crucial — and they've received over 700 tips to date.
“That's a ton of tips,” Bryan said. ”But a lot of it really has to be sifted through carefully.”
A lot of tip calls end up being vehicle sightings, and sometimes the volume can become problematic for investigators, he said. “But you still want to encourage the public to be involved, that's for sure.
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“A lot of the time it just takes that one good tip.”
Bryan said the mystery surrounding the case is fuelling the public's interest. Investigators have not yet disclosed where Bosma was killed, how he died, an exact time of death or a motive.
“It's because the investigators — and god bless 'em, it's what they have to do — are keeping things close to the vest,” Bryan said. “There's still a few people out there that are unidentified in this and we don't know how close they are to catching up to these people.”
Millard has not been talking with police and is “executing his constitutional right to remain silent,” his lawyer said. Police are still searching for at least two other suspects.
“But if it turns out that it's just over the theft of this vehicle … If that's the only motive, that they were going to steal this truck, then wow — this is very over the top,” Bryan said.