Police say many witnesses and parents at the scene of the shooting have not cooperated with investigators.
An annual survey of Indiana teens finds the use of tobacco, vapor, alcohol and drug use on the decline.
Authorities say around 13 people have been arrested based on pending warrants against them unrelated to the slayings.
A recent study published in the Journal of Pediatrics found teenagers are apparently using e-cigarettes to smoke marijuana in addition to tobacco.
The IPRC says the increase however in marijuana use is up across all age groups.
Indiana now ranks number two in the nation for teen dating abuse.
Indiana legislators are considering a new rule that would limit cell phone use while driving for motorists of all ages.