I also received an email regarding another victim identified as Hector Tapia who apparently was also a US citizen and who was not related to criminal activities.
According to PGJE this is correct, this means that two US citizens and a 11yr old boy were the victims of this failed attack.
The following is the translation of the AFN story on Tomas and how he was initially identified as a sicario by some "sources".
TIJUANA BC March 18, 2013 ( AFN) . The young man who died the on Sunday in "Los Arenales" was not part of any cartel nor called Eloy Espinoza Ramos, this was pointed out by people close to the victim who further reported that his death was due to a lack of competence of the municipal police of Rosarito who left him bleeding to death in the Jeep where he was found.
His real name they say is Tomás Llamas who worked in San Diego, where he apparently was a vendor for the DoD (or authorized to enter their staff facilities) this according to a credential shown to AFN Tijuana .
In the last hours "sources" claimed that this man was in fact named Eloy Espinoza Ramos and that he was part of the group of Alfredo Arteaga Arzate alias "El Aquiles" and his brother René alias " La Rana " . They branded him as the author of several deaths, including that of a former police "commander".
People close to Tomas Llamas ensure that the latter worked at National City for an automotive company, in charge of loading new vehicles into trucks to be delivered. They also said he was 26 years old.
According to them, this young man came to Baja California with three other friends who were visiting Playas de Tijuana Real del Mar, but then decided to move to " Los Arenales " knowing the environment that is held every week there.
They said they decided to stay in that site because there was music, after that, the attack in which the young man was hit in the abdomen took place. Other sources referred to AFN that they took Tomas with them for medical care and were received in the military roadblock who allowed them to continue on their way to a hospital but elements of the local police intercepted them and did not let them go on their way despite pleas from friends who saw him bleed to death.
The believe Tomas died as a result of the negligence of the local police and was a victim not only of the shooter, but of the insecurity prevailing in Baja California.
People who identified him as Eloy Espinoza sent photographs showing a strong resemblance to Llamas, but the bear outlines of Tomas, on one side of the mouth are thicker than those of Eloy.
Some of his friends told AFN "we are well doing young guys , tired of so much corruption and crime, and the lack of opportunities and looking for a better future."
http://www.afntijuana.info/seguridad/26137_no_era_sicario_fue_victima#ver_nota