Manhunt continues for suspect in connection to the killing of Brian Thompson

(NBC, KYMA/KECY) - Authorities continue a massive search for the man suspected of killing UnitedHealthcare CEO Brian Thompson.

Thompson was on his way to speak at UnitedHealth Group's investor conference around 6:45 a.m. Eastern Wednesday when a gunman approached him from behind outside of the New York Hilton Midtown Hotel.

Police found a backpack in Central Park that they believe belongs to the suspect.

Authorities found Monopoly money inside, but four sources familiar with the investigation told NBC News on Saturday that no gun was found in the backpack.

According to a police official, the person of interest in the fatal shooting may have left New York City through a busy bus terminal. The search for the suspect has now expanded to Georgia.

As authorities continue their search security measures are being enhanced at UnitedHealthcare headquarters.

In addition to an increased police presence, crews have installed fencing around the headquarters in Minnetonka, Minnesota.

New York police have offered a $10,000 reward for information leading to the capture of the shooter and the FBI has added $50,000 to that reward.