Has he even tried?
Sheriffs and other law enforcement officials can’t issue indictments. That is the job of a prosecutor. In most jurisdictions in America, law enforcement turns over evidence of alleged criminal activity to the City Attorney, the County Attorney, the District Attorney, the state Attorney General, the U.S. Attorney or the Attorney General of the United States depending on the appropriate jurisdiction for the crime that is alleged.
If a prosecutor feels that there is probable cause to convene a grand jury in the hope of issuing an indictment, then the prosecutor will convene a grand jury of citizens. In modern day criminal law practice, if a prosecutor wants an indictment, the grand jury will indict.
There has never been a grand jury investigation in any jurisdiction in the nation looking into any of the alleged crimes concerning Barack Obama’s eligibility to be president.
It does amaze me that no grand jury has been convened over Obama eligibility with so many different crimes being alleged (forgery, document tampering, Social Security fraud, election fraud, identity theft, etc). Those who have challenged Obama’s eligibility have used the civil side of the legal system nearly exclusively, filing more than 200 lawsuits.
Obama could have been running for reelection with a grand jury investigation hanging over his head. That might have changed the outcome of the 2012 election.