Four boys, 10-12 years old, face arson charges for Eugene stadiu - KPTV - FOX 12

Four boys are facing arson charges for a massive fire at Eugene's Civic Stadium on Monday.

Eugene investigators said four boys were playing with fire in the press box, but the flames got out of control and burned down the ballpark.

Investigators said that as flames spread Monday night, the panicked boys jumped a chain-link fence, hopped on their bicycles and fled.

But parents of a fifth boy who left before the fire tipped off police on Wednesday.

Investigators said Thursday they don't believe the boys intended to destroy the park, but they haven't given coherent reasons for using a lighter to ignite material such as wood, drywall and leaves.

Police said the incident was not related to fireworks.

One of the boys is 10 years old, the others are 12 years old.

The fire began at around 5:30 p.m. Monday and escalated quickly with flames twice the height of the stadium and thick black smoke that could be seen for miles.

Nearly 40 emergency personnel responded to the scene of the fire Monday. The fire was deemed under control after about 90 minutes, but crews remained at the scene for hours.

Eugene police issued an evacuation notice for a two-block radius surrounding the stadium while firefighters battled the blaze.

According to the website for the Eugene Emeralds, the team played at Civic Stadium for 41 years before moving to the University of Oregon's PK Park in 2010. The Emeralds share PK Park with the Ducks baseball program.

Civic Stadium was built in 1938, according to the history of the Eugene Emeralds.

Copyright 2015 KPTV-KPDX Broadcasting Corporation. All rights reserved. The Associated Press contributed to this report.