Last month I gave a presentation on security threats at sports events and their implications at Baskent University. Istanbul is one of three finalists for hosting the Summer Olympics in 2020.

Today’s explosions at the finish line of the Boston Marathon, killing two and injuring dozens persons, underscore the fragility and susceptibility of sporting events. In light of that event, security at the London Marathon on April 21^stis expected to strengthen.

Sadly, we should not be surprised of political violence at sporting events.In April 2008, a Tamil Tiger suicide bomber killed 15 and injured over 100, when he detonated himself at the start of a marathon race near Colombo, Sri Lanka. The attack killed the Highway Minister of Sri Lanka, who also served a government peace negotiator, and the marathon coach of the Sri Lankan national team.

Awareness of this issue came to light in September 1972 when eight members of Palestinian group Black September entered into Munich, Germany’s Olympic Village and stormed the quarters of the Israeli delegation. They murdered two Israelis and took nine more hostages, demanding the release of more than 200 Arab prisoners, mostly in Israel. After a day of failed negotiations with German authorities, the terrorists and hostages were ferried to a nearby air base, where a plane was waiting, as the terrorists requested. But a nighttime firefight between German snipers and the terrorists left all nine hostages dead, along with five of their captors and a sniper.

Security efforts at the Olympics have expanded since that incident with varying results. In July 1996, a knapsack bomb exploded at the Centennial Olympic Park in Atlanta, Georgia, killing two and injuring 120 people. Eric Rudolph, who pled guilty to the attacks and serving life in prison, undertook the attack in support of the violent, anti-abortion group, the Army of God.

In Winter 2002, the first post-9/11 Olympics, security measures ranged from a restricted flight zone over Salt Lake City and nine Olympics venue to sharpshooters. No terror incident arose at the event. The security matrix was expanded during recent Olympic games, including in Beijing in 2008 and London in 2012.

Political violence has also targeted the soccer events globally. In July 2010, twin suicide bombings at an Ethiopian restaurant and a rugby club in Kampala, Uganda, killed 76 and injured at least 85 people. Al Shabaab took credit for the attack. The victims were watching the World Cup matches.

In July 2007, two suicide bombers in Baghdad killed 50 people  and injured 135 celebrating the Iraqi national team victory in the Asian Cup finals. In May 2002, ETA detonated two car bombs near the Bernabeu stadium in Madrid, Spain, the night before the European Champions League match between Real Madrid and Barcelona. About two dozen people were injured in the attacks.

In March 2009, a dozen Lashkar-e-Jhangvi terrorists attacked the Sri Lankan cricket team’s bus near the Gaddafi Stadium in Lahore, Pakistan. Eight Pakistanis were killed and six Sri Lankan national team members were injured.

The effects of political violence on sporting events can be gauged according to various parameters, including: fan attendance, athletes, sponsorships, broadcasting, media coverage, revenue, and security measures, among others.

Security responses to such threats comprise: expanding physical and technological security measures; public-private partnerships; intelligence gathering, analysis, and dissemination; and improving crowd control and terrorism indicators.

Dean C. Alexander is Director of the Homeland Security Research Program and Associate Professor at Western Illinois University.  He can be reached at dc-alexander@wiu.edu