Double murder? Abortion?

Ok the situation is: Mrs. Kelly Mullan is impregnated on May 17th 2003. One month later she is walking through a park at night with her husband to ?'break the news' to him and suddenly her husband is knocked unconscious and she is murdered. Two months later Mr. Gary Shunts gets pulled over for speeding. The police officer runs the plates and finds that the driver, Mr. Shunts, has a warrant out for his arrest for the murder of Mrs. Mullan. During the investigation of Mrs. Mullan's murder, the murder investigator finds Mr. Shunts' fingerprints on the knife he dropped at the scene, finds Mr. Shunts' skin and blood under Mrs. Mullan's fingernails and he dropped his credit card at the scene (he is not a very good murderer.) So Mr. Shunts is arrested and arraigned on charges of assault on Mr. Mullan. Now here is the question, will he get arraigned on charges of the murder of Mrs. Mullan alone? Or will he be accused of a ?'double murder'? Will the ?'killing' of the unborn baby of Mrs. Mullan's count as a murder?

Different parallel universe the situation unfolds thusly: Mrs. Kelly Mullan is impregnated on October 17th 2003. One month later when she informs her husband that she is pregnant he pressures her to abort the child and she complies. They made the choice together and went through with the abortion. In both situations the ?'life' of the child is ended.

Legally, in the first situation, is it considered as a ?'murder' that the baby is killed? What about in the second situation? Change the scenarios to 5 days after fertilization of the egg or in the midst of the 3rd trimester. When is it murder and when is it not? When is abortion justifiable and when is it not? I am, at this point, not interested in theoretical moral philosophy. I am curious of what exists in our real judicial system right now that explains these situations. We can discuss the theoritical legal implications later.