Dr. Keffler was a genetic scientist recruited by a rogue NID group to create a human-Goa'uld hybrid in order to obtain access to the Goa'uld genetic memory, in the episode, 7.19 "Resurrection".
Dr. Keffler was the son of a German Nazi scientist who believed that any means necessary should be taken in order to obtain the knowledge of the Goa'uld. He felt strongly that the human-Goa'uld hybrid he created in his laboratory in a warehouse in Los Angeles, California, USA, was the means to access the Goa'uld genetic memory and save the Earth. He was able to grow the "specimen" Anna, after 45 failed attempts, a little over a year before his lab was discovered by the NID. Using nanite technology stored at Area 51, he was able to advance Anna's age very quickly and she appeared to be a young adult woman when she was found.
NID Agent Malcolm Barrett ran the investigation at the site and solicited the help of SG-1, sans Colonel Jack O'Neill, to determine what kind of work was being conducted at the lab. He had Dr. Keffler held in an interrogation room, hoping that the scientist would reveal what he knew about what had happened there.
Dr. Keffler programmed Anna so that he could activate the Goa'uld part of her with a remote control. He could also inflict pain on Anna, a way of conditioning her to obtain the information he sought. The Goa'uld Sekhmet was discovered in a canopic jar similar to those in which Iris and Osiris had been banished, and it was her DNA that Keffler used to blend with Anna's.
When Dr. Keffler discovered that his associates were going to report his inhumane treatment of Anna (he kept her in a locked glass cage), he activated Sekhmet in her, let her loose, and allowed her to kill the 32 people at the site. Anna, the human side, did not remember this incident. The Goa'uld part of her could control her just as if she were a host to an actual symbiote. While she was out, Sekhmet set a bomb, powered by naquadah, in order to kill Dr. Keffler, but she was caught before the bomb was discovered. It wasn't until Daniel Jackson found the combination for the ark containing the bomb illustrated in a charcoal drawing Anna kept in her cage that they found the bomb and determined that it was about to go off within 16 hours.
Anna said that the images she drew were from her dreams. When the ark was opened to reveal the bomb, Daniel requested that Anna attempt to access her memories to find a way to deactivate it. Anna said that Daniel was just like Dr. Keffler, and upon reviewing the video tapes of their sessions together, Daniel was able to discover what that truly meant: Dr. Keffler only wanted to have information from her and didn't treat her like a human at all. Daniel said that they'd do everything they could to help her, but Major Samantha Carter discovered that the Goa'uld DNA would eventually overtake Anna's body and kill her. In order to prevent this horrible suffering, Dr. Keffler implanted a biotoxin in Anna's skull which could be released via the same remote control he used to make Sekhmet surface.
When Anna decided to help Daniel find the combination to stop the bomb in order to save all of Orange County, she bravely placed herself in a trance through meditation. Daniel helped her through the process and she saw the evil within her and she decided that she'd kill Dr. Keffler herself. She was able to escape from her cell and she tracked him down after he was able to free himself from his interrogation room by faking ill health. Anna found him and and killed him. Realizing that she couldn't be helped, Anna activated the biotoxin implanted in her skull and killed herself. Anna was still able to help everyone else, however, because she had drawn the combination to disarm the bomb and Daniel discovered the drawing in time.
--DeeKayP 21:13, 16 Jul 2004 (PDT)