'The Flash': Cisco's Discovery Changes Hunt for Mrs. Allen's Killer

Cisco Joe West Flash - H 2015
Cate Cameron/The CW

[Warning: Spoilers ahead for Tuesday's episode of The Flash, "The Nuclear Man."]

Cisco (Carlos Valdes) made a discovery on Tuesday's The Flash that could change everything.

While helping Joe (Jesse L. Martin) solve a mystery, he discovered that blood recovered at the murder scene of Barry's mother belonged to Barry (Grant Gustin). And not little kid Barry — adult Barry. That means that Barry somehow traveled back in time, and was around when Reverse-Flash (presumably) killed his mother.

See more 'The Flash': Every Major DC Character on The CW Series

The discovery wouldn't have been made possible without Cisco's working relationship with Joe.

"Their partnership compliment them really well. Joe has that natural capability of being a detective and assess the situation given a small amounts of clues," Valdes tells The Hollywood Reporter. Cisco is the muscle in that he can make all of the technology that makes things happen. Their relationship is really possible because they are able to cover so much ground."

Gustin has teased the time travel element of the show before, with Harrison Wells (Tom Cavanagh) having been shown to have access to future newspapers and technology. 

"We are diving deep into the time-travel element and it is going to be wild," Gustin told THR in January. It looks like that moment will arrive next week, judging by the promo for "Fallout." 

Check it out here:

The Flash airs at 8 p.m. on Tuesdays on The CW.

Email: Aaron.Couch@THR.com

Twitter: @AaronCouch