Both have criminal records. Neither is a saint. Based on the records of both of them, if past behavior is a predictor of future behavior, then this was an unfortunate combination that met up that day.
Although one of them has pled no contest to arguably more serious crimes.
I believe you're mistaken about one of the individuals. What I found on Sacramento County Superior Court website was NO RECORD for Joshua Allen Atkins of any criminal case. There is a Joshua Ellis Atkins with a record that goes back to 2000, so it doesn't appear to be the same Joshua Allen Atkins (he wouldn't have been an adult in 2000 in order to have this type of record - as a minor). Joshua Allen Atkins is listed as being 22 years old.
The other individual, Minor Leon, has a felony assault case filed on 5/28/10 along with several other felonies to which he pleaded no contest to a single felony assault. Then on 7/22/11, he was against charged with several felonies including assaults, batteries, etc., and pleaded again no contest to a single misdemeanor assault. And remember, this kid is 19 years old. How many other 19-year-old do you know who have a felony AND misdemeanor assault conviction on his/her record?
It will be interesting how this investigation progresses (or not).