The day before Pennsylvania father Mark Short shot his entire family before turning the gun on himself, he took his three children to Hershey Park, an amusement park near their Sinking Spring, Pennsylvania, home, PEOPLE confirms.

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On Monday, during a news conference on the August 6 murder-suicide, Berks County prosecutors detailed the weeks and days leading up to the tragedy.

The newly-released information confirms speculation the Shorts were having marital issues.

According to prosecutors, Megan and Mark Short had agreed to separate. In June, police were summoned to a Philadelphia hotel on reports of a domestic dispute involving the Shorts, and on July 18, officers were called to the couple’s home after another argument, prosecutors said.

On July 19, Mark Short, 40, purchased a .38 caliber revolver handgun and ammunition, prosecutors say. Less than a week later, Megan Short signed a lease for her own apartment, as she’d announced to her friends in a Facebook post.

Prosecutors say things only got worse for Mark Short: He received a demotion at his job on August 1. Four days later, Short spent a day at Hershey Park with his three children – 8-year-old Liana, 5-year-old Mark and 2-year-old Willow.

When she was a newborn, Willow made national headlines after surviving a risky heart transplant performed the week after she was born.

Investigators said Megan Short, 33, planned to move in to her new apartment the same day as the murder suicide. Prosecutors allege Mark Short offered to rent a moving truck to facilitate his estranged wife’s move.

Sometime after noon on August 6, Megan Short stopped answering her phone, prompting a relative to call the Short’s neighbors to check on her. After nobody answered the door, Megan Short’s mother contacted police at 2 p.m. that afternoon, who entered the home and discovered the scene.

Medical examiners eventually concluded Mark Short died from a self-inflicted gunshot wound to the head. Authorities say they recovered five empty bullet casings from the home’s basement.

Prosecutors say Mark Short’s fingerprint was found on a live round still in the chamber of the gun found alongside his body. They add that an analysis of the the suicide note left behind shows Mark Short authored it.

A portion of the note included a confession, according to the prosecutors’ statement.

A funeral mass for Megan Short and her children was held Friday.

In an interview last week with PEOPLE, Megan’s cousin, Laurie Swingle McGuinness described her as a strong, doting mother who was “consumed with love for her children.” [/restrict]