Ostertag returned to music in 1989 and toured with Fred Frith's Keep the Dog. He also appeared in Nicolas Humbert and Werner Penzel's 1990 documentary film on Frith, "Step Across the Border". Ostertag released "Attention Span" in 1990, featuring Frith on guitars and John Zorn on saxophone. Ostertag followed "Attention Span" with the release of "Sooner or Later", his musical response to his years in El Salvador and the first part of a trilogy to treat the themes of grief, anger, and joy. In 1992, The Kronos Quartet commissioned a new work from Ostertag. This commission produced the landmark work . Ostertag composed the piece using a recording of the AB101 Veto Riot in San Francisco. Ostertag originally conceived as a collaboration with writer/painter/photographer/film maker David Wojnarowicz, but David was ill with AIDS. When David died before the collaboration could take place, Ostertag made a second, solo piece from the riot recordings, "Burns Like Fire", and dedicated it to Wojnarowicz. In 1993, Ostertag formed Say No More, a virtual quartet, with vocalist Phil Minton, drummer Joey Baron, bassist Mark Dresser, percussionist Gerry Hemingway. The group's music was actually composed by a computer and sampler from separate individual performances and then released as "Say No More" in 1993, the live – "In Person" in 1994, "Verbatim" in 1996 and "Verbatim Flesh & Blood" in 2000.