Trustworthy faces could be measured by happy smiling.

HAPPY FACES ARE CONSISTENTLY THOUGHT MORE TRUSTWORTHY

A happy face discriminates a man as more trustworthy than sad looking. A baby face is consider as the freshness of mind is likely found in a happy looking face.

Trustworty model

Dr. Chisrtofer Olivola who is  co-author of the study published in trend in cognitive science said "Although we would like to think our judgment and choice are rational Impartial, consistent and solely based on relative information-the truth is that they are often biased by superficial and irrelevant factors". An Ideal look for a criminal could be measured as prominent factor. Good smiling appearance and high eyebrows are sign of trustworthiness and honesty.