The DA confirmed Friday that it has assigned investigators to work with the California Horse Racing Board.
Meantime, there is a call for a congressional committee to investigate treatment of racehorses at Santa Anita Park following the deaths.
Congresswoman Judy Chu wants the House Energy and Commerce Committee to investigate the treatment of horses, not only at Santa Anita but at racetracks across the country.
MORE: Santa Anita Park creates new health and safety rules
Racing at the park has been suspended indefinitely after the number of Thoroughbred deaths started to skyrocket since late December. The park also announced the track would ban race-day medication and the use of riding crops.