GARDAI (police) are investigating a sinister criminal campaign in which threatening letters and shotgun cartridges were sent to two government ministers by anti-in vitro fertilization protesters.Threats and bullets were also sent by post to two fertility clinics near Dublin. A hoax bomb was also sent to one of them.A live shotgun cartridge and a threatening letter were delivered to Health Minister Mary Harney's office in Hawkins House, central Dublin, and to the offices of Enterprise Minister Micheal Martin, who is also a former health minister, on February 29.On the same day, the Sims fertility clinic at Dundrum, Co. Dublin, was also sent a threatening letter and a hoax bomb. The letter was scribbled and contained offensive material. There was concern the device would require a controlled explosion, but this later proved unnecessary.Taoiseach (Prime Minister) Bertie Ahern described the campaign as "nasty and sinister.""I'm not too sure what kind of mentality is behind that. But the Gardai are investigating it," he added. "It does happen from time to time but thankfully not very often."Dr. Tony Walsh of the Sims clinic described those who sent the letter as "social terrorists."He said the letter contained an accusation that the clinic was "murdering embryos." He called on the government to introduce legislation that would define clearly the status of an embryo in Irish law to protect those working in reproductive medicine.He said there was a history in Ireland of a "crank element" where reproductive medicine was concerned, including when the pill was first introduced into the State and said, "It seems to be that reproduction and fringe groups go hand in hand."A long-time advocate for clearer legislation in this area, Dr. Walsh said it was not easy to practice reproductive medicine with "this vagary of legislation in the background.""Indecision and failure of the legislators to move quickly on this allows fringe elements to mount an operation like this. Now that it's hit home with the politicians, it might give them some idea of what it's like at the coal face," he said.Details of the threat to Harney emerged first. Then on Monday the government confirmed that Martin also received a threatening letter and a shotgun cartridge from a previously unknown group calling itself the Irish Citizens' Defense Force.Martin may have been targeted because of his previous position as health minister. In 2000, he established the Commission on Assisted Human Reproduction. Its final report in 2005 was considered controversial because of its majority conclusion that embryos should only attract legal protection after being implanted in the womb.In addition, a majority of the commission approved egg, sperm and embryo donation, as well as surrogacy. A majority also approved some forms of embryo research.However, its findings have never been formally adopted by the government.The Clane clinic in Co. Kildare, which was also targeted in the campaign, said it received a letter that contained "deeply upsetting" threats to staff. Security precautions had been taken as a result.