The lawyers for accused letter bomber Guido Amsel began cross-examining a Winnipeg police detective who prepared a document known as an information to obtain in order to get a DNA sample from Amsel.

The pre-trial cross-examination granted by provincial court Judge Tracey Lord allows Amsel's lawyers to ask questions about an August 2015 RCMP lab report which contained results of a swab of Amsel's hands.

A preliminary test found traces of an explosive substance but needed to be verified with a second report, court heard earlier this week.

Amsel's lawyers have taken issue with the exclusion of the results of the second test from the information to obtain, which came back negative.

Amsel's lawyer Saheel Zaman asked Det. Ravi Misir if he knew the first test was presumptive and why he didn't include that detail in the information to obtain.

Misir told court he was aware of the presumptive nature of the test and was aware it needed lab confirmation, but that it’s not his practice to label tests as presumptive.

“I refer to them as the kind of test they are,” Misir told court.

He told court the report was entered into the Winnipeg police computer system on August 28, 2015 and that he completed the information to obtain two days earlier on August 26, 2015.

The Crown has objected multiple times during the cross-examination, taking issue with some of the questions being asked of Det. Misir.

"We're talking about his knowledge of the report and the questions should be confined to that," said Crown attorney Chris Vanderhooft.

Amsel's defence lawyers are challenging the legality of the blood sample taken from their client.

Amsel is facing five counts of attempted murder and multiple explosives-related charges after letter bombs were sent to two Winnipeg lawyers and his ex-wife in July 2015.

He has pleaded not guilty to all charges.

The trial is expected to get underway next month.