One of the suspects can be eliminated by figuring out Summer's time of death.

Have a look at the Officer Notes notebook.

The first page of the notebook gives an equation for calculating time of death.

Have a close look at the loose officer note.

The loose police note mentions that Summer's rectal temperature was measured 10:53AM and recorded to be 96 degrees Fahrenheit.

The first page of the police notebook gives the Glaister equation for calculating time of death. The equation is: (98.4 - rectal temperature of victim)/1.5= hours since death.

If we apply this calculation to Summer, we get: (98.4-96)/1.5=1.6, which translates into one hour and 36 minutes. Working backwards, if Summer's rectal temperature was measured at 10:53AM, she would have been killed one hour and 36 minutes before that, which puts her time of death at approximately 9:17AM.

Which suspect has an alibi for 9:17AM?

*Note that the autopsy tells us Summer died "within minutes of receiving the final impact", so we can assume she died, at most, a few minutes after her killer left.

Examine the temporary tattoo carefully.

The temporary tattoo lists a website: www.blackrosestattoos.com

Read the Seattle Times carefully.

The Seattle Times reports a mugging on September 14th at 9:15AM and lists the location. Find the approximate location of the mugging on the Highland Park map.

The mugging happened at the intersection of Devonshire and Keele Road, which is about 8-10 miles away from Still Rock (where Summer was murdered). It would be impossible for someone to commit the mugging mentioned in the article at 9:15AM and murder Summer at 9:17AM.

The Seattle Times article mentions the mugging suspect has a distinctive tattoo. 

If you're not sure who to eliminate, visit the blackrosestattoos website (www.blackrosestattoos.com) and look carefully at the pictures on the website.

The Seattle Times reports that the mugging suspect had a tattoo of a pitbull and the words "Game Over". This is a such a unique tattoo, that if someone has it, we can assume they are the suspected mugger. On www.blackrosestattoos.com , there's pictures of clients and tattoos they've gotten. One of the tattoos is a tattoo of a pitbull with the words "Game Over". The client listed for the tattoo is Dante Turner. Dante is the mugging suspect, and so Dante could not have murdered Summer.

We can eliminate Dante because he lacked the opportunity to murder Summer using the following pieces of evidence: Officer Notes notebook (for time of death equation), loose officer note (gives us Summer's rectal temperature, so we can calculate her time of death as 9:17AM on September 14th, 2019), the Seattle Times magazine (which tells us that the person who committed a mugging at 9:15AM on September 14th, 2019, has a tattoo of a pitbull and the words "Game Over"), and a temporary tattoo (to access the website www.blackrosestattoos.com, which shows Dante has a tattoo of a pitbull and the words "Game Over").