did you get them directly from pgr? Try to get them trough the Canadian embassy
If the police certificate is required for a person living outside Mexico
The certificate you will need is called the Informe de datos registrales, also issued by the Procuraduría General de la República (PGR).
While your application is being processed, the visa office where your application is processed will contact you when it will be time to obtain the Informe de datos registrales.
If the visa office where your application is in process contacted you and requested the Informe de datos registrales, you must do the following:
You must send to the Canadian Embassy in Mexico City, for each person for whom a police certificate is required:
1) Two sets of original fingerprints that meet these standards:
rolled and flat impressions of all ten fingers taken with black ink
full name, date of birth and sex of the applicant
the name and address of the police agency
the signature of the officer taking the fingerprints
How to have your fingerprints taken?
In Canada: Please contact a fingerprinting agency, or go to the closest local police station.
All other countries: Please go to the closest local police station. (In some countries the Mexican Embassy or Consulate will be able to assist you)
2) Three photographs of the front, and three of the right profile: passport size (With no makeup, earrings, glasses, beard, moustache, sideburns–no exceptions)
3) One legible copy of your passport’s bio-page (the page where your picture and full name appear).
4) Quote your file number, your name, date of birth, and the name of the visa office, Canadian embassy or consulate or Case Processing Centre where your file is.
Do not send any other documents or provide any payments.
Send the above to:
Canadian Embassy, Immigration Section
Miguel de Cervantes Saavedra 193
Col. Granada
11520 Mexico, D.F
The Canadian Embassy in Mexico will request the Informe de datos registrales for you and will forward the results directly to the visa office where your application is in process. This will take approximately 60 to 90 business days.