TIMELINE: The Michelle Martinko murder case

Michelle Martinko's murder went without an arrest for 39 years. Investigators stayed on the case over the decades, with developments occurring incrementally.

At approximately 6:30 p.m.: Michelle Martinko drove her family's 1972 Buick Electra to Westdale Mall. She had left a school banquet, and intended to purchase a new winter coat.

At around 2:00 a.m.: Martinko's parents reported Michelle missing to police.

At around 4:00 a.m.: Police discovered the Buick in the northeast part of the Westdale Mall. She had stab wounds to the face and chest. Investigators at the time concluded the homicide to be "personal in nature."

Investigators announced that they had discovered new DNA evidence in the case. They uploaded the new evidence into the Combined DNA Index System (CODIS). This database matches samples from unsolved crimes to samples from convicted offenders. No match was made through CODIS.

Cedar Rapids police received a tip through Linn County Crime Stoppers, which led to a possible suspect. The DNA of the suspect did not match the DNA from the crime scene they had on file from 2006.

Police issue a press release to ask for the tipster from December to contact them again, saying the information he provided was credible and that they would most likely be able to contribute more information.

Investigators used services from Parabon NanoLabs to do DNA phenotyping, a process that gives an estimate of physical appearance and ancestry using DNA samples. They used this process to create facial composites, which were released by the police department at a press conference.

Through September 2017, authorities had collected more than 100 new tips for the case. None of the tips led to an arrest. DNA evidence ruled out more than 100 people from the investigation.

Based on DNA evidence that investigators collected covertly, they ls question 64-year-old Jerry Lynn Burns at his workplace in Manchester, where he denied committing the alleged killing. He was unable to offer an alternative explanation for why his DNA would have been found at the crime scene.

Officials announced Burns was arrested and is facing a first-degree murder charge in the case.