Heidi Klum and her former bodyguard/boyfriend Martin Kirsten visited an attorney's office in Brentwood on Tuesday -- apparently to dissolve his employment contract after their breakup. Reports claim the two parted ways personally and professionally late last month ... so now begins the clean-up.

No doubt Kristen had an ironclad confidentiality agreement as part of his employment contract and when their professional relationship turned romantic, maybe the terms of that agreement changed slight. Now, as they've decided to part ways, it seems Heidi's bought in a lawyer to help make it a clean split. The two were very icy with each other this morning -- walking to their cars together, but not saying a word. And note Heidi's holding her big tote back in between her and Martin -- as a buffer. Neither said goodbye to each other when they parted ways and Heidi went home ... Martin Kristen went elsewhere. OVAH!

Last week People.com reported they had split after a year and a half of dating, adding that the breakup actually happened in early January.

"Martin was there for her during a challenging time in her life and it was something she will always be grateful for," a source told the magazine. "Life is about timing. He was incredibly supportive and they were there for each other, but they're moving on now. They still have a great friendship."