MINNEAPOLIS — The Latest on the deadly explosion and partial building collapse at a Minneapolis school (all times local):

11:50 a.m.

The local medical examiner says the two people who were killed during an explosion at a Minneapolis school died from blunt force injuries sustained when part of a building collapsed.

The Hennepin County Medical Examiner on Friday identified the victims as 47-year-old Ruth Denise Berg and 82-year-old John Ferm Carlson, both of Minneapolis.

Berg and Carlson were longtime employees of Minnehaha Academy, a private Christian school with about 800 elementary and high school students.

Investigators from the National Transportation Safety Board are on site trying to determine what caused Wednesday's natural gas explosion. The blast ignited a fire and caused a portion of a school building to collapse.

___

9:20 a.m.

The private school in Minneapolis where an explosion and partial building collapse killed two people and injured nine others is planning a memorial service for the school custodian who died in the blast.

Minnehaha Academy said on its Facebook page that the school will hold a service Sunday at 6 p.m. for John Carlson in the lower and middle school chapel. The school says Carlson's family will receive visitors before the service.

Carlson and another longtime school employee, receptionist Ruth Berg, were killed during the explosion Wednesday. Fire officials say their bodies were found on the south side of the collapsed portion of the building.

A team from the National Transportation Safety Board is on scene to determine what caused the natural gas explosion. The NTSB is investigating because it has jurisdiction over gas pipelines.

___

8 a.m.

Administrators at a private Minneapolis school where an explosion and partial building collapse killed two people say the start of classes for some students will be delayed about two weeks.

In a memo to parents, Minnehaha Academy President Donna Harris says the start date for the damaged upper school will be postponed from Aug. 23 to Sept. 5. The academy's upper school houses the high school. The lower and middle school campus is about a mile and a-half away. It was not damaged in Wednesday's blast.

A team from the National Transportation Safety Board arrived in Minneapolis Thursday to begin the painstaking task of determining what caused the natural gas explosion, which killed two school workers.

Harris says administrators are working to find a facility to house classes for the upper school.

The Christian academy has a combined enrollment of about 825 students.

___

12:05 a.m.

One man who was injured in a deadly explosion and partial building collapse at a Minneapolis school remains in critical condition.

The family of Bryan Duffey released a statement Thursday saying they've seen him make progress since Wednesday's blast at Minnehaha Academy. The statement also says Duffey will need more surgery.

The private Christian school says Duffey is a facilities team member.

School receptionist Ruth Berg and custodian John Carlson died in the building collapse. Two other adults remained hospitalized Thursday in satisfactory condition.

National Transportation Safety Board investigators arrived at the scene Thursday. NTSB member Christopher Hart says investigators are looking into whether the explosion occurred while a gas meter was being moved.