(NewsNation) — Following a recent spate of seemingly random attacks, violence at the hands of strangers might seem like it’s on the rise, but currently available data doesn’t clearly confirm or debunk that perception.

Incidents including a shooting spree that killed three people in Detroit and a punch that landed one man in a coma in New York City have made headlines in the past several weeks.

Data surrounding the frequency of violent crime between strangers, however, is murky — complicated by gaps in local police reporting, unsolved cases, and at times the nuanced relationships between the victim and offender.

In 2019 — the most recent data available — 28.3% of homicide victims were killed by someone they knew other than family members, according to the FBI. Of those victims, 13% were slain by family members, and nearly 10% were killed by strangers. The relationship between murder victims and offenders was unknown in 48.9% of murder and nonnegligent manslaughter situations.

Maria Tcherni-Buzzeo is the director of the PhD criminal justice program at the University of New Haven and serves as the research director of the Liberty Initiative. At the beginning of each semester she asks her students the same question: do you think crime has gone up, down, or stayed the same?

“A lot of students think that it’s going up, even though it has been going down for (about) 25 years,” Tcherni-Buzzeo said.

According to the Council on Criminal Justice (CCJ), the number of murders across 23 cities included in a July report dropped by 2% in the first half of 2022 compared to the first half of 2021. The murder rate, however, is still 39% higher than it was pre-pandemic during the first half of 2019.

Historically, murder has declined substantially nationwide since the early 1990s. The homicide rate for the cities included in this year’s CCJ study was about half of what they were for the same cities in 1993.

“The (student) impression is based on the media reports and based on crime dramas,” Tcherni-Buzzeo said. “They’re very popular. The real situation kind of gets lost in the shuffle.”

Crime as a whole is more likely to occur between people who know one another or are related, according to the Bureau of Justice Statistics. Information about violent offenders who victimize strangers is less comprehensive, but individual reports offer a kind of snapshot into specific trends throughout the past several years.

One study, published in 2012 by the Bureau of Justice Statistics, determined that strangers committed about 38% of nonfatal violent crimes including sexual assault, robbery, aggravated assault and simple assault in 2010.

That represents about 1.8 million nonfatal violent crimes — a 77% decline from 1993, according to the Bureau of Justice Statistics.

Crimes committed by strangers were more likely to include a firearm, but between 2005 and 2010, victims were more likely to be injured by a known offender rather than a stranger, according to the report.

Additionally, from 2005 to 2008, about 43% of homicides known to have been committed by a stranger occurred during a robbery or argument.

In some cases, “until the last minute, it’s not even clear who is going to become the victim and who’s going to become the offender,” Tcherni-Buzzeo said.

“Our belief in the just world makes us want a situation where there are innocent victims and there are evil offenders,” she said. “And the justice system works and punishes the evil and helps the good. I totally understand that. I like it and I love the idea of something like that happening, but it’s not what is actually happening.”