April 3 is the 93rd day of the year (94th in leap years), with 272 days remaining.
- 1888 — "Jack the Ripper"'s suspected victim, Emma Elizabeth Smith, is found.
- 1896 — Amelia Dyer is apprehended.
- 1908 — Bruno Lüdke is born.
- 1958 — Gennady Serebrennikov is born.
- 1962 — Tony Vick is born.
- 1973 — The "Alphabet Killer"'s victim, Wanda Walkowicz, is found.
- 1980 — John Charles Bolsinger is apprehended.
- 1980 — Emy den Boer is murdered by Koos Hertogs.
- 1981 — Charles Robert Huber Jr. is murdered by Bruce Lindahl.
- 1985 — The "Bible Belt Strangler"'s suspected victim, Tracy Walker, is found.
- 1988 — Victoria Bell is murdered by William Choyce.
- 1988 — John Cannan's victim, Shirley Banks, is found.
- 1989 — Leslie Ann Noyer is murdered by Charles Stevens.
- 1990 — Holly Suzanne Tarr is murdered by Cleophus Prince Jr..
- 1991 — Kwon Soo-sang is murdered by Lee Choon-jae.
- 1991 — Becky Phillips is murdered by Beverley Allitt.
- 1992 — Earl Richmond is apprehended.
- 1996 — Ted Kaczynski is apprehended.
- 1997 — Laura Smither is murdered by William Reece.
- 1997 — Bradley Edwards's victim, Ciara Glennon, is found.
- 1999 — Ion Prodan is apprehended.
- 2011 — Alevtina Kuydina is murdered by Artyom Anoufriev and Nikita Lytkin.
- 2012 — Hao Yunhua is murdered by Zhang Yongming.
- 2013 — Megan Lancaster is murdered by Neal Falls.
- 2013 — Joanna Dennehy's victims, Lukasz Slaboszewski and John Chapman, are found.
- 2014 — Tommy Lynn Sells died.