Just a thought, no accusation. Bear with me.
Out of competition tests are significantly more rare than in-compeition. Dopers who have been caught report that it is easy to time your doses so that you are well clean by competition-test time. Dope in training, race clean.
Even more, Diego Estrada was not tested in 2014 by the USADA. He is not listed in the statistics:
http://www.usada.org/testing/results/athlete-test-history/
[that itself is a surprise, given is successes at the 20k, 12k and 5k champs]
Given his (and Martinez's) incredible training sessions, his "under-performance" may be due to cleaning up by race time; that he doped in training, significatnly enough for those incredible session, and then stopped as competition time approached. I don't know the biochemistry of EPO well enough to know how long a benefit tapers off without maintenance, (and I'm not going to let anyone hear tell me without some cited research) but it is worth considering...