[[WMG: Alejandro's English is so poor that he couldn't understand Sylar's threats.]]
So how'd he even find, much less read, the article about the murder of Mrs. Gray? If it were a Spanish translation, it would have worked, but the headline was clearly English.
* Maybe he read the article by copying and pasting it into Babel Fish. Since Maya could understand English, he figured that she would have an easier time reading the original rather than a garbled translation.
* Or maybe he caught on the same way their white tourist friend realized they were wanted- he saw Sylar's picture in his search, and he knows just enough English to recognize "homicide" and "mother".