There appears to be some bad blood between Calgary police and the chief medical examiner's office.   

Detectives have been forced to get a search warrant to obtain evidence held by the examiner's office from the murder investigation of six-year-old Meika Jordan. 

The young girl died at hospital a day after sustaining severe injuries in her home in Calgary's northeast. Calgary police have charged her father and stepmother with second-degree murder in the death.

In a 55-page court application to obtain a search warrant, police explain they wanted to seek the opinion of forensic pathologist Dr. Chris Milroy, who specializes in pediatric deaths.

They believed Milroy may be able to narrow down the time frame of the injuries sustained by the young girl. 

But before the Ontario pathologist could proceed, he required evidence acquired by the Calgary medical examiner's office during Jordan's autopsy: microscopic slides, X-rays and photographs.  

Police have been trying since July to get this evidence without a search warrant.

Court order often required, says Alberta Justice

In email and telephone exchanges detailed in the application, chief medical examiner Anny Sauvageau appears upset police went directly to Milroy before consulting her.  

"It has always been the policy of the OCME to release such material only from pathologist to pathologist. In this case, I won't release the material to Dr. Milroy either," Sauvageau wrote in an email to Major Crimes Insp. Cliff O'Brien, who requested the evidence.

A spokesperson for Alberta Justice says it's standard practice for the medical examiner's office to require a court order before receiving items like the ones requested, and the evidence would be released following the court order.

But police sources told CBC News this is anything but standard procedure, and said Sauvageau has refused to voluntarily hand over the evidence for a fourth and final time.  

"I am afraid you will have to seek judicial authorization. It is very unfortunate," Sauvageau wrote in another email to Insp. O'Brien.

Michelle Davio with Alberta Justice acknowledged the rift between departments but says it's a relationship that is being worked on.  

"There's tensions in the system and I know the chief medical examiner is working to ensure that the relationship with Calgary police flows smoothly, appropriately and legally."  

Davio called the relationship between the crown, police and medical examiners "extremely important."  

"[They] are working towards the same goal — they all want to see cases get to trial and they want the evidence to be strong," she said.

The search warrant will be served to the medical examiner's office on Tuesday.

Calgary police were contacted for comment, but were not available on Monday.